This is a post that Janek made for 'Mars Attacks' that explains some of the differences between the Soviet, Czech and Polish T-55s. Since most T-55s in movies (especially Hollywood ones) do not feature actual Soviet T-55s, this guide can help determine where the tank was built.

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USSR manufactured tanks mostly for their own army; Czechoslovakia exported most of its T-55 for East Germany, Egypt, Syria ("commercial" clients), etc.
I saw this movie; this tank has oval-shaped gunner sight and coax machine gun I'm sure - only in Polish and Czechoslovakian vehicles - that's the easiest way to distinguish the origin of tank.
Czech T-55: http://commons.wikimedia.org/wiki/File:File-Ex-Czechoslovak_or_ex-Czech_T-55_3.jpg
Soviet T-55: http://commons.wikimedia.org/wiki/File:T-55_Imperial_War_Museum.jpg
Polish T-55: http://commons.wikimedia.org/wiki/File:T-55_front_RB.jpg

Difference between Polish and Czech include gun mantlet, engine deck and many others.

Polish gun mantlet:
http://www.hrcappuccino.org/articles/okohodac/T-55 okohodac/T-55_43.JPG - smooth structure
http://picasaweb.google.com/polar123tank/T55_Poznan_Cytadela#5072882962191242674 - smooth sturcture
Czech gun mantlet (identical to the Soviet vehicles):
http://data3.primeportal.net/tanks/scott_tremblay/t-55/images/t-55_17_of_35.jpg - riveted
http://svsm.org/gallery/T-55_little/IMG_0747 - raised "X"

Engine deck
Polish (square air cleaner hatch on the left, opened to rear side - like in T-54):
http://picasaweb.google.com/polar123tank/T55_Poznan_Cytadela#5072882992256013794
Czech (asymetric, opened to the right side - same as in Soviet original):
http://www.trevalan.com/Milipics/Images/0001_0023L.JPG

After unification of Germany (GDR bought T-55 from CSSR [about 1800] and Poland [about 330] many were sold to Western countries; Arab vehicles were captured by Israelis and widely used by IDF (see http://www.imcdb.org/movie_94716-The-Beast-of-War.html ), later withdrawn and sold.