Do these 5 punch dots represent reloading times?
Nice early headstamp!
Robert Mellichamp, in A Gun For All Nations The 37mm Gun & Ammunition, Volume 1, !873-1913, calls these marks “reload punches”. So your suspicion that these are reload marks was correct and it appears the cartridge case was reloaded 5 times.
Which page number are you quoting? I was going through the book late after a whole day of work, my excuse for being “blind”.
Sorry I should have listed the page earlier, an example and description are on page 379, lower right.