That's a good point.  My guess is yes, but a little differently than later models.

Does an '87 have the same tendency to backfire and pop?

i have a screaming eagle pipe, on my stock 87. i have done nothing with the jetting. My Bike Is loud, it roars and the sound over powers my b-in-law's sportster that has stock muffs. it does backfire once in a while and does it  when coming down example: i'm in second gear high rpms (cus i'm speeding of course ) i let go of the throttle to put clutch in and gear up to third and POP, push on the throttle, max out third gear, release throttle to put clutch and gear up to fourth and POP then i'm in forth and i'll let off  the throttle and POP but like i said it doesn't always do it. also it vibrates a whole lot more. man the vibration was so hard my wife started crying about her knees hurting after a long ride and when i say crying i dont mean complaining i mean tearing and crying i had to carry her in the house.  Lastly the BLUE PIPE . Whats odd is ive seen pics of peoples pipes that are blue and they blue from the header. my pipe is only blue on the screaming eagle and its right in the center of the pipe. A big blue spot.  I really love it thought lots of fun. I'm still getting that performance carb from lancer though. Just waiting on the new throttle cables so that he can send it. I"ll let you all know how that acts.

Have either of you adjusted the idle mixture screw?  

That is all I have done to mine and I almost never get any backfiring.  Even on hard decels.  Joe