Well Derek, you are in luck.
The base plate I have is square, with four mounting holes. The round area the vise rides on is right at 4"...... the distance from the slot that the locking lever rides in is right at 1.5 inches center to center. If that distance is close, the locking lever on the side will work. The center hole is 1/2"!!
Here's the kicker, I had a Littletown 140 sitting on it, and its' base measures right at 4-1/4"~4-5/16", so I think it would work for the vise you have. I used it for some time, until I got my big Columbian vise, so I know it will work if the other holes distances match.
My original plan for the Littletown was a solid mount, as I bought it without a base for that intended purpose. I'm gonna mount it on a solid base for travel with my blacksmith setup for small twisting/filing jobs.
The mounting plate/base mentioned above that I had under it was from an old Wilton or Columbian that was junked some time ago with a cracked/broken jaw.
If you want the mounting base, lockdown lever and bolt, and center bolt to hold the two parts together, just say the word. I still have to send the Thorsen's I have in reserve to you anyway (I've been waiting, carrying the list I printed in my wallet, hoping to find more for you, but I haven't run onto any in the last few weeks).
If your center hole and lock lever hole is right at 1-1/2" on center, then it'll work, I'm pretty sure.