There is no hard rule about alignments and classes, or classes and races. The book specifies generalities, and also gives counter examples. For example, in the Paladin class under the Oath of Vengence Tenets (page 88 of the Player's Handbook), it says that Oath of Vengence Paladins are often Neutral or Lawful Neutral in alignment.
A neutral good tiefling rogue is perfectly acceptable.
Well, if you don't mind making a pact with some powerful entity, you could get 2 levels of warlock. This will give you access to a few spells, some of which perhaps being interesting (both stats and flavor-wise) for your character. But most of all, this will give you access to 2 invocations.
One of these invocations should be Devil's Sight, which grants you the ability to see through any form of darkness, magical or otherwise, for up to 120 feet. This is more than enough to cover the 15 feet of the darkness spell. Cast it on your clothes, and bring terror to your enemies.
While this is a good strategy (generally favored by blade pact warlocks), it has some limitations. While under the effect of the darkness spell, your allies cannot see you. As such, any spell requiring line of sight that they would like to cast on you simply cannot work. Healing you might be problematic, as it requires your allies to be able to touch you. They might know that you are smack in the middle of that sphere of pure black darkness but, once they get inside, it's suddenly not so easy to find you anymore.
These limitations also affect your enemies, however. Any attack from the outside of the sphere should have disadvantage as your enemies, even if they can approximate your position, can't exactly see you to aim properly. Enemies inside the darkness should also suffer from disadvantage when attacking you, unless they possess some form of blindsight or a similar ability. When you attack them, you should have advantage on the roll since you are functionally invisible for them.
The biggest cost of this strategy is the fact that it requires multi-classing. While the lvl 19 and 20 abilities for monk would not really be missed (realistically, few campaigns will reach these levels), it will still set you back 2 levels in obtaining you other core monk powers. Note that doing this would get you 2 invocations, however, and that some of them can be quite interesting for a ninja-esque character:
Armor of Shadows (cast mage armor at will, which might be better than
using your wisdom for AC if its under 16),
Eldritch Sight (cast detect magic at will),
- Eyes of the Runekeeper (allows you to read anything, even languages
you don't know... useful for spying!),
- Gaze of Two Minds (share the eyes of a willing target, more spying!),
- Mask of Many Faces (disguise self at will!), etc...
TL;DR
Sacrifice 2 monk levels and multiclass as a warlock. Gain some minor but potentially useful spellcasting, as well as the ability to see through magical darkness and one more ability of your choice!
Best Answer
Ask the FLGS owner about his return policy. Tell him you're specifically interested in getting the most recent printing of this book, but you're concerned that the only way to tell for sure is to open it up.
He MAY be willing to pull off the shrink wrap off and help you check, or he may have one from the same delivery batch that's already open. At the very least, he MAY be willing to take it back subject to store return policies.
If this FLGS is the kind of store that has tables and people hanging out, you could also ask around if any of the regulars had purchased a PHB from this recent delivery batch, and if so could you take a look to see what revision it is.
This is not a guaranteed solution, of course, but at least in my experience the FLGSes I've done business with have generally been understanding of us geeks and our attention to detail. If nothing else, you can ascertain how fully screwed you'd be if you bought it and it wasn't what you wanted.