Yes, weighted is the preference. But if these were available I would strongly consider using anyway, due to being such a close match to the original WTC $25, and it would be a value chip that doesn’t get used a lot in my games. Just want to fill out my set.
So with news if @Tommy's upcoming purge, I was cleaning out my PM inbox.
@pokerman was the one who offered these to me. He wasn't interested in splitting, IIRC, but he had lots of chips, all the way through $500. Looks like @pokerman was last on about a month ago, so maybe he'll chime in if he has any for sale.
At the time, he had:
336 of $1 chips
1068 of $5 chips
301 of $25 chips
56 of $100 chips
72 of $500 chips
And I recall he said he could get more.
Anyway, hope that helps you find what you're looking for.