When in the 1800s? Toff would be the perfect choice here, but it isn't found any earlier than 1851, and I would be shy of putting it into the speech of anyone until at least 1855 (maybe a bit braver if they were in the Midlands, East or South East of England).
After that though, it would be a common word that matches your description perfectly.
(It's still in use, but not as much as before, having peaked in the first half of the 20th century).
Edit: Comment says this is set in the very beginning of the 19th century. That rules out toff and even haw-haw (around 1825), and beerage is right-out (1880s).
His nibs is an interesting example, but just too late (first attested 1821).
You could take a punt on haw-haw and his nibs on the basis that the first spoken use is likely slightly earlier than the first printed, but it would be a stretch.
Nob is an interesting one and might be apt. It's often understood as a contraction of noble, but while that's probably an influence, white-knob also spelled white-nob is found in the late 18th century until early 19th meaning an upper- or upper-middle class person in reference to the white wigs they would wear and it got contracted to nob. Hob-nob was likely also a further interest.
In any case, nob hits your meaning and was in use in your time, and white-knob also hits it, was in use, and has firmly died-out since, so it might be favoured as giving more temporal flavour.
Best Answer
Depends a bit on the context and your intent. There are two common ones in professional contexts.
If this fragment is part of a description of the necessary qualifications for a job, and you want to tell applicants that they must have worked a similar job in the past, then the usual format would be something like "To be a lab tech, prior professional experience is required." This specifically requires experience in a formal position - usually paid - working with the requested skillset.
If you only require the applicant to have worked in some kind of live environment (as opposed to only receiving training) then it would typically be "prior hands-on experience". In this case, informal jobs or practical experience during education is considered sufficient.
I think "To work as a lab tech, prior work experience is required" would be a bit strange, but I do see "Prior work experience" listed as a bullet point in lists.
Generally, "on-the-job experience" isn't used to describe a required qualification, but rather something one might gain - e.g. "Our co-operative education program offers college students a chance to gain on-the-job experience while still in school."
"First-hand experience" generally refers to having experienced some event in person, rather than job experience - e.g. "We are looking for contributions from readers with first-hand experience of a bear encounter." It would probably be strange in this context.
"On-site experience" generally refers to experience working in a locale where you aren't necessarily required to be (usually closer to the customer or otherwise beneficial for your development) during a job. For example, "Sally gained a lot of valuable on-site experience when she went overseas to work with the client at their office in Germany, rather than staying at the home office." It wouldn't be necessarily incorrect here, but the meaning would differ.