Sorry I sent you boys down the rabbit hole.
Basically, the QR date thing was spurred by:
1. A stub someone was claiming QR was opening for Purple and Bad Co, even though only Purple was on the stub (4/24/87).
2. That person's email to me saying "the QR date is on setlist.fm." (which, again, given the spotty accuracy of that, is suspect.)
3. But remembering that QR was likely IN Philadelphia during that time, at the initial Mindcrime sessions.
4. Also recalling that dates during the Rage years are not always complete, since the band was between management and booking agents, and DeGarmo was doing bookings.
all those factors sent me on a mission to figure it out. And I still haven't. I do think the likelihood of it is there, as other acts (some local, some national that were in the area) were being added as the first band on the bill ahead of Bad Co. and Purple. So if Queensryche was in town, and had their touring rig (again, very possible), I could see them doing a show, particularly for a quick pay check while in the studio. But this was the first I heard of any post-February 1987, but pre-Mindcrime touring gig from them.
At some point I will figure it out.