You have understood the phrase perfectly: it is another way of saying "If you had asked..."
(My personal opinion is that it is a pointlessly pompous way of saying it; but I didn't get a vote.)
The base idiom is BE to VERB, where BE is the appropriate form of the verb be and VERB is the infinitive form of any verb. It means, approximately, "suppose", in both the senses in which that quirky word is used.
Thus, in the indicative (real) mode it means be supposed or expected to do whatever VERB names. For instance, I am to go to London tomorrow means "I am supposed to go" or "I am expected to go to London tomorrow".
In the irrealis mode, expressed with the past form, it takes the other meaning of suppose, "assume as a hypothesis". If I were to go to London (or, alternatively, Were I to go to London) means "Let us suppose that I go to London" or "If we assume that I go to London".
In your example, the author asks you to "suppose" not something which happened in the present, which would be expressed as "If you were to ask world leaders today", but something which happened in the past, a few hundred years ago. You have to 'backshift' the expression from present to past.
But you can't do that in the ordinary way, by using the ordinary past form of BE, were—because you've already used up that form in the present. The workaround in English for expressing a past irrealis is to employ the appropriate form of HAVE + the past participle of VERB: "If you were to have asked world leaders a few hundred years ago".
Notice that the same workaround is employed in the ordinary, non-pompous way of expressing the same thought: "If you asked world leaders today" is backshifted as "If you had asked world leaders a few hundred years ago".
This looks like a perfect construction, but it's not; it's the past irrealis construction.
Keep in mind that a present perfect casts its predication in the present tense. It does not narrate past events, it mentions past events which give rise to a present state.
That is why formal English does not permit a present perfect to be used with a temporal adjunct which does not include the present moment, the Speech Time at which the sentence is uttered. (You will occasionally find this rule violated in improvised, conversational discourse; but even there it is comparatively rare.) Thus, this is acceptable:
okI have often visited London.
But this is not:
∗ I have often visited London in the 1990s.
Today, in the 20th century is a timeframe which excludes the present. Consequently:
Sentence 1) is acceptable if it appears in a text written in the present century, but would be of questionable acceptability if written fifteen years ago.
Sentence 2) is acceptable if it appeared in a text written during the 20th century, but it would not be acceptable if written today.
There is a great deal more about this at What is the perfect, and how should I use it?, especially §§ 3.1 Grammatical meaning, 3.2 Pragmatic meaning and 4. When and how should I use the perfect?.
∗ marks a usage as unacceptable
Best Answer
It's an If Clause Type 3: if + Past Perfect, main clause with Conditional II.
Example: