Saw the Red Sox play tonight and later walked their team store.  On display were many pieces of game used equipment and balls for sale, much of it signed.  All the signatures looked good (that is, they looked genuine), even those signed by players who’ve been deceased for a quite some time.  I’m curious about a few things and was wondering if anybody might take a moment to enlighten me.  

First, is it generally accepted among serious collectors that merch purchased from such places is legit?  Anybody encountered questionable items being sold by teams?

I noticed a COA from Claudia Williams for one of her father’s signed bats.  (I think the company name is “Green Diamond?”). I’m assuming this was John Henry’s joint enterprise with Ted.  The signature looked good to me.  Anybody ever encounter forgeries/questionable signatures with those COAs?

Is it reasonably safe to assume that players have signed these items specifically for the team unless otherwise note?  (Such as the Claudia Williams COA, for example.)  In other words:  Can I be reasonably certain that such merch is not being purchased from another party and re-sold?  

I know this is a lot of questions, so thank you in advance to you for your time.   I saw a couple of highly desirable, reasonably priced pieces tonight that I’d like to buy, but am hesitant only because I’ve never purchased from such a store before.

Thank you.