Some, but not all thirdgen cars, were equipped with a secondary cross member as seen below. While the five OE rubber mounts (four donuts and the main trans mount) nicely dampen vibration, they also make the car feel sloppy, I think, especially compared to a one-piece OE cross member or an after market version. At the very, very least, I'd recommend a one-piece OE with an OE rubber mount.

JamesC

 

i have that on my 92. Its quite the contraption, but nothing like the liquid filled mounts.
It will find its way to the scrap yard one of these days.

 

It seems the 2 piece crossmember was used on some early V8's and most V6 cars. If that crossmember is original to your 85 Iroc, that's the latest V8 car I've ever heard of with that setup. My 86 Firebird parts car (base model LG4/auto) had the 1pc, as did my 86 T/A's.

 

Those 2 piece crossmembers aren't nearly as bad as the "donut" transmission mount crossmembers some '88 and '89 cars I believe came with (including mine).

Consider yourselves lucky