East Germany had only two panzer divisions (not counting the armor assigned to motor rifle units), which always received modernized equipment first, so that's where the T-72's began to appear in the late 1970's. By 1981, several companies worth would likely have been operational, the vast majority in the 9th Armored Division, which would've been part of the thrust across the North German Plain.
The T-72 was a much more capable and modern tank than was the T-55 and likely would have given a much less dismal account of itself against NATO forces:
I plan on doing one battalion's worth and this week I've finished my first company:
Two more companies and a battalion command stand and I'm done!!