It is discovered that these items are being held at the Westing Estate, which is revealed to be infested by a rather large den of mirelurk.
After retrieving these items, return to Cronin, in which he will reward the Sole Survivor very well.
Find a Signed Baseball
Moe Cronin in Diamond City wants me to find three baseball relics said to have been left behind in the old Westing Estate.
Find a Signed Catcher's Mitt
Find a Signed Baseball Card
Return to Moe Cronin
I've recovered all the baseball relics for Moe Cronin. Time to collect my reward.
I recovered a set of baseball relics for Moe Cronin in Diamond City.
Moe Cronin is dead. Whatever reward he would've given me for those baseball relics is gone with him.
The signed items count as quest items, and cannot be sold as an alternative to completing the quest normally. Because of this, the items also do not weigh the Sole Survivor down, and all have a weight of 0.