gearhead

By the side of the baseplate that has the adjustable screws sticking through (narrow spacing), it's a neck pickup. That much I'm sure of.

I'd think the 496R.

Need to measure DC resistance on them to even begin figuring out what they are for sure.

Definitely not "T" Tops. The bobbins would have a T on them. And resistance is higher than original T Tops. I would guess by the DC resistance they are 490R/498T set.

I would think it's early '70s. Here ios a listing on reverb. Gibson T Top Embossed Covers And here is a thread in the Gibson forum. Embossed Gibson PU Covers

I would guess maybe a 500T/496R combo would be close. There really aren't many specs to be found for the Epi pickups besides the DC resistance.

http://legacy.gibson.com/Products/Electric-Guitars/2017/USA/Les-Paul-Classic/High-Performance.aspx About halfway down the page it gives specs for a Super 57.

Pole spacing should be 52mm for the bridge and 50mm for the neck. I suggest that you purchase original Gibson pickup covers. Covers will affect the Q of the pickups which will shift the resonant peak. Using junk covers made of brass etc won't be a good thing. JMO.

First, I'm not real sure what you mean by "both the humbucking and string coils", but I have one of these in an old Melody Maker D Reissue. I have the bridge PU about 1/16" or a bit more from the strings. The pole pieces are adjustable, but I doubt you can tell much difference in raising individual screws a little. If you raise or lower the whole PU, or one side, say 1/16" to 1/8", you can tell some difference. Do what I do, try adjusting it to how it sounds best to your ears.

If possible I would try to contact the manufacturer.

Well I can't hear what kind of pitch the feedback is, but I will say that the covers can change the resonant frequencies and capacitance of the pickup. If you have a big enough soldering iron to unsolder one of the covers you might want to try it.

I CONCUR, FINISH! ALL GOOD!

LOOKS RIGHT! EPI COLORS ARE THE SAME AS GIBSON.

I really like the new Inspired by Gibson line. Been looking hard at them! LOL. Yea, like I NEED another guitar! Have 9 gits and a bass now! But NEED has nothing to do with it. GAS!

What does the end of the truss rod look like under the truss rod cover? Could you post a pic?