... has the same fork crown as yours
... is a touring frame w/ rack lugs
... the ser# is on the bottom bracket
... where the lug covers the bottom of the down-tube
... and there is a ‘dimple’ on the back of the bottom bracket between the chain stays (Ron’s ‘trademark’?)
... your ser# might be covered w/paint ?
... mine is a ‘respray’
... I guess it may have come thru ‘Bikecology’ in the late ‘70s

... It’s good to see a post from somebody who worked there
... I saw a ‘70s catalog on the web
... I tried calling but nobody remembered anything about build dates or ser#’s