Dave, the Welch's Howdy Doody glass is a very rare glass I think. I had not heard of one until just a few weeks ago, when I was trying to find out the names of the characters on the bottom. I found this web site link ...
Howdy Doody Glass
which had a Howdy Doody glass with only the Hazel Atlas logo on the bottom, like the one you found.
So I guess there are some out there,but definitely very scarce.
I was going to put the photo (with permission from the seller which I have permission already) on the next COllector Glass News, so if you can send me a picture of the one you have I would put that photo in the newsletter also.
Thanks. Great find.