Ok, I don't think I am going for the TT baster, I feel like the TTDO will be a better match, it doesn't appear that there is a hard and fast rule for either matching top and bottom but it looks to me that I should be looking for, what I would call, a fully marked DO bottom with
"the griswold mfg co." over the top and the trademark on the around the bottom. Thanks for your help, it is interesting that the #7 and possibly the #6 have the angled patent date. I would like to see one of those one day. I really like the smaller DO's for what ever reason.