Joe, I am not an expert on these early 1903 rifles - but your Rock island s/n 27686 appears to be original to me. The Conrad Nelson 1908 cartouche
on a stock without cross bolts is very early and quite rare. I sent an email to John Beardicon about your post on this forum, Mr Beard is the expert on
these early Rock island rifles and I hope he will see your photos and post some comments.