The wipers on the stanchions, or the seals internally?
Shermans use the stanchions as a closed damper of sorts, seperating the damper oil (inside the stanchion, sealed off around the damper rod) and the lubricating oil (in the bottom of the lowers, sealed off by the stanchion wiper).
Weeping on the stanchions isn't appealing, but it isn't detrimental to performance either. Try pulling the lowers off the fork, 2 bolts and you're done, empty out the old oil and only put a small amount of fork oil in. I think it's only a few ml, between 5 and 20, check the manual. It might be a case of the old user overfilling the lowers with oil after doing a pre-sale rebuild, and the problem may go away. If it still weeps after a decent amount of riding with little oil in the lowers,
then worry about new seals.
You don't want to waste money buying things that you don't need though, that's for sure