How can I find out which Pearl drum set I have?

well, the badge on the front of each drum might say what model it is. usually it'll say something like "forum series" or "export series". if its an older set, it might not have that info on the badges. in that case, there should be a label on the inside of the shells with a serial number. you might just have to look up the serial number and that should give you an indication of which type of pearls you got.

Pearl Drum Badges

If you can find a serial number anywhere on the shells, take the number and type it into google with the word "Pearl" in front of it. Like this:

Pearl 4587DFG (or whatever the real serial number is)

Then see what the results say. Pretty good chance it's online somewhere.