Certainly western intelligence was keen to get their hands on Soviet ground equipment. The Israelis were always a good source of captured Soviet equipment. The Soviets liked to showcase their latest export models in the region, and the Arab states had a habit of losing them. Even as far back as the '56 Suez crisis, the US would obtain captured equipment, and received six T-62's after the Yom Kippur war. (Miglietta, American Alliance Policy in the Middle East, 1945-1992)

The T-64 presented a challenge, because the Soviets never exported it.

Of course, particularly the Arab-Israeli conflicts proved as a big testing ground for military equipment on both sides. Both friendly and enemy equipment was evaluated, and examples captured and shipped back to the respective superpowers when applicable.

The Americans received a large amount of systems, sometimes older or export models, but on occasion more modern technology.

After the Six Day and Yom Kippur conflicts the US had received access to the following Soviet systems captured by the Israelis:

BMP-1 (tested at aberdeen proving ground during development of XM-2 MICV's 25mm bushmaster cannon)

Mig-21E (Have Donut project)

SA-2 (information used in Vietnam conflict for SEAD)

ZSU-23-4 (Project HITVAL in 1974 at White Sands)

The Soviets were similarly interested, but as I don't speak Russian much of their documentation is not of much use to me.

They did receive a captured Israeli Magach in 1982 or 1983 which was outfitted with Blazer ERA and the M-111 "Hetz" 105mm APFSDS which proved capable of penetrating the glacis of contemporary Soviet tanks during testing at Kubinka. They then copied and improved upon Blazer in Kontakt 1 ERA which began appearing on Soviet tanks shortly afterwards, and mounted an additional 16mm add on plate to their other tanks to thwart the 105mm round. (Unfortunately for the poor west germans who had been impressed by it an chose to license produce it for themselves)

Going a bit further back the British got to examine a T-54 when it ended up on their embassy grounds during Hungarian Uprising. When examined it was found that the the Centurion lacked the firepower to penetrate the T-54 head on. The Conqueror could do it but that was meant to be a limited production heavy tank. The result was that the Centurion ended up being up-gunned.