I was able to weigh the bat and it came to 36 ounces. Considering the date of the bat and Speaker’s records indicating he never used bats under 37 ounces until his post-playing career (and 40+ oz pre-1920) I can rule out (however unlikely it was in the first place) specific game use, at least by Speaker. There are clear indicators of period use IMO including what appears to be cleat marks.
Still I am fascinated by the markings on this bat. After more research I found exactly one example each of the engraved ‘Partridge Boston’ label and the World’s Championship decal, both on Louisville Slugger bats:
The ‘Partridge Boston’ engraving is found on this Eddie Collins LS 40 E.C. model decal bat:
Meanwhile the World’s Championship decal is found on a period LS 14 inch mini bat, leading me to think the decal logo was used for a very specific event/series and possibly sold or given away as a souvenir:
Again, welcome to any input longtime bat collectors may have! Thanks, Matt