Made me curious.
Here's what Wikipedia says (usually a pretty decent resource):
"East Germany – 202 T-54s were ordered in 1956 from the Soviet Union and delivered between 1956 and 1957. 488 T-54As and T-54AMs were ordered from Poland and delivered between 1959 and 1964.
1766 T-55s and T-55As were ordered in 1964 from the Czechoslovakia and delivered between 1964 and 1980.
333 T-55s and T-55A(P)s were ordered from Poland and delivered between 1965 and 1973.
362 VT-55s were ordered in 1964 from the Czechoslovakia and delivered between 1965 and 1969.[7] Passed on to the unified German state".
Near the end of the page, the following is provided for East Germany, from here:
link
East Germany
T-54Z (Z for Zusatzausrüstung – additional equipment) – East German modernization of T-54 similar to T-54AM.
T-54AZ (Z for Zusatzausrüstung – additional equipment) – East German modernization of T-54 similar to T-54AM.
T-54AMZ (Z for Zusatzausrüstung – additional equipment) – East German modernization of T-54 similar to T-54AM.
T-54T (Panzerzugmaschine ohne Bergesatz) – East German development with recovery and welding equipment. 10 made on Polish-made T-54A chassis. NATO code: T-54(A).[119]
T-54TB (Panzerzugmaschine mit Bergesatz) – similar to
T-54T, but with 140-t winch. 10 made on Polish-made T-54A chassis. NATO code: T-54(B).[119]
T-55AM2B with bin on left-hand-side of turret.[37]
T-55 NAL NRD – East-German modernization of T-55. It wasn't finished because of the political changes in 1990.
T-55T – Modified VT-55A with push bar and splashboard across glacis plate in service with the NVA.[37] T-55T with towing unit on the glacis plate with a mount that protrudes over front of vehicle. Front towing unit also has a flexible 'eye' permanently fitted. NATO code: T-55T.[37][119]
Minenräumfahrzeug (Pz) – Prototype mine clearing vehicle developed by the East Germany. Two Versions: equipped with KMT-6 M2, EMT-5 electronic mine clearer and an lane clearer WLWD.[37][120]
equipped with KMT-5[120]
T-54 M1975/1 – Experimental East German roller/flail combination mine clearing vehicle.[37] T-54 M1975/2 – Flail only variant of the M1975/1.[37]
T-55TK – East-Germany received 119 Czechoslovakian JVBT-55A's between 1968 and 1979 and called them Kranpanzer T-55TK.
BLG-60 (Brückenlegegerät) – East German/Polish scissors-type bridge layer.[37] Development started in 1965 (one year after the BLG-34 project was cancelled [121]) and the first vehicle was delivered in 1967. Almost 200 BLG-60's were built by STAG Genthin and SKET Magdeburg. BLG-60 trainer – Modified training bridge.[37]
BLG-60M – Improved BLG-60 that makes it possible to attach 3 bridges together to bridge gaps of up to 52 m. Entered service from 1973.[121] BLG-60M2 – Because of the introduction of the bigger T-72 tank, some 30 BLG-60's had to be widened by 20 cm.
It doesn't list the number of T-55AM2Bs, but you've got that mentioned above.
As you can see above, some T-55s, and/or T-55As were delivered as late as 1980, which I find rather remarkable, given the age of the vehicle design. No doubt, it probably had some upgrades, as I mentioned just above, to make them a bit more effective in combat than those delivered back in the 1960s.
Here's some useful info on variants and upgrades over the years, for both the T-54 and T-55:
link