Posted By:
Marc S.Scott-
A few ideas:
1) You could get the autographs officially authenticated, but that is expensive and cumbersome, esp. for the autographs you purchased (e.g. relatively common, not huge value)
2) The best method to easily use is comparison of signatures from reliable dealers. One dealer is James Spence. He was always a great guy, and he now heads up the PSA/DNA authentication service. He has both Flick and Griffith signatures in stock, so I am sure you could e-mail him for scans. Jim Stinson (of Stinson Sports) is also a realiable dealer that typically has those signatures in stock. You could request scans from him, too. Quality Autographs of Virginia is also a pretty reliable dealer -- though I have not dealt with them in a long time.
3) Mark Baker published a book in 1991 "SCD Baseball Autograph Handbook". It is readily available online in used form, and it is a pretty helpful book for a novice/new autograph collector. For $10-, it is not a bad investment if you are going to purchase more autographs down the line.
The best advice in collecting autographs is as follows: Find a dealer you can trust. If the autographs costs much less than you would think you it should, huge red flag. And the best advice is to just look at as many authentic examples as you can find (usually through trustworthy dealers, etc.). Eventually, you will be able to see similar mannerisms/characteristics of the authentic signatures.
From my experience, the Griffith signature looks fine. I do not know enough about Flick's signing habits to provide much of an opinion on that one. Sorry. Hope this is helpful.