I think there was a reason for the period, because they did it for multiple years, even into 1992 when the format of the card back entirely changed. But I don't think it was a way to generate interest in the product. That would definitely be a stupid way to do that. My best guess is that it was an internal thing for tracking or QC purposes. Say for example they did have two different production facilities. If Donruss people open packs and find substandard cards, they know which facility the cards came from by looking for the period. Same theory could apply to the *Denotes versus *Denotes* error. This with the period could identify 4 different printing lines.

Quote Originally Posted by Boo Radley View Post
I think you're giving them WAY too much credit. For one, it's got to be the stupidest variation in all of baseball cards. Secondly, the only reason to deliberately create a variation is to cause buzz about your product -- manufactured rarity to increase demand and therefore sales. If you were going to do something like that, you wouldn't do something like remove a minute piece of punctuation on the back of the cards that 99.999% of people are never going to notice. Also, you'd make them actually rare. I don't know of any premium for either version.

I think it's benign. With the exception of slight tonal differences, Donruss backs are pretty much unchanged from year to year in that period. I wouldn't be surprised if one of the outsourced printers or one of the in-house pieces of equipment just never got changed.