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