[drc]

Authentic items are regularly framed and matted, so I don't think framing and matting itself is a sign of anything.

Stamped signatures and some machine-printed signatures can often be identified as such in an online image. For example, the stadium balls with stamped on team signatures simply look stamped on-- there's no ink flow. Even autopens can look unreal due to a lack of change in pen pressure/ink density.

One thing is if your purchase is machine printed, you'd have no trouble proving it's a fake beyond a doubt for the sake of getting your money back, as an expert could testify it wasn't hand written. There would be no dueling signature 'experts' required.

And, as always, know the seller. An reputable autograph expert isn't going to sell you a ink jet copy of a Joe DiMaggio autograph.