Which version of Pro
Opening up the .prt file in a text editor and looking at the first line yields the necessary information.
For example:
#UGC:2 ASSEMBLY 1068 440 0 1 1 15 2100 2000050 0000b335 \
#- VERS 0 0 \
#- HOST
In this listing, the 2100 signifies v21 or 2000i and 2000050 is the build