Interesting.
I checked and have all three. However, only the "Mini Contest Winning House" has no vet reward tag, and only that one is facing another way, whereas two of Bobar's face the other way (which also do not have the vet reward tag).
I would reckon that there are four different ones, two of which may be older, two may be newer:
Contest 2004 Winning House Design (1st year veteran reward)
Contest Winning Custom House Design (1st year veteran reward)
Then, they may have been changed to
Contest 2004 Winning House Design
Mini Contest Winning House
I say this because I placed, and axed, a "mini contest winning house". These also seem to be more available than their "1st year veteran reward" counterparts and are the names on the vet reward gump. Why did they change, and when?