Help dating a possible ink stamp
 

Hi All.

I have a circa 1930s 18" baseball bat "stamped" by Babe Ruth and Lou Gehrig. There is no known history to the bat apart form it was bought from a large baseball collection (which included many signed Ted Williams items) at an estate sale. I am under no pretence that these signatures are authentic, however after doing some reading regarding stamped autographs, I'm not sure these are stamps. Is there any way to date ink without sending it to a forensic scientist? Ie, did they use brighteners in ink post ww2? Would a black light work? Any thoughts if this might be ghost signed? Thanks for your help!!!