Mike that problem isn't new although prior units would have had stickers at least to tell you the version. There are Windows 8 and 8.1 stickers underneath every laptop with it installed they would say Pro if that were pro as I have seen a few however, if you play the odds, the failure of 8 came mostly from businesses who never adopted it so 98% of the units you see are standard for that reason. The standard versions just say Windows 8 and there were no Home Premium or basic versions anyway. Remember also they did away with oem and retail in 8.1 so we do not have to worry about that issue either for finding the right disk.
A system builders disk would have all versions on it and the disk identifies the Coa which determines which version to use so having one of them would be the easiest way to solve the issue and I have seen same available for sale on eBay.