I'm only chiming in because a board member asked me about this, and because this is exactly the kind of thread that I think we need to see more of in this sub-forum - we're talking about vintage autographs and we've got people participating who have expertise.
...but I'm not one of them
But I can say that a very similar situation came up for me when I was looking for a Gehrig autograph. I asked David A about it, thinking it was an absurdly ugly Gehrig, and David educated me on the fact that Gehrig's autographs changed over time and that there were idiosyncrasies with Gehrig's autograph within a time period as well, depending on various factors. I had complete faith in David's assessment at that time, and no reason to change my thinking now.
So, with Gehrig there are some ugly ones that are real. On the other hand, there are plenty of Gehrig autographs out there that are obviously real - beautiful signatures in ink - so there's no reason to consider one that you aren't very confident in.
I never did buy a Gehrig, because I never felt personally confident enough in my own ability to authenticate them. I still feel that when it comes to high-end autographs, if you aren't willing to do the research and learn enough to feel more confident in your own opinion than in JSA's or PSA's, then you should keep your money in your pocket.