I had a Mossberg 144LS. The LS stood for Lyman Sight. Same basic barrel profile and stock and barrel band. As I recall from the bench and a rest it was pretty accurate. And same sights globe front and Lyman rear sight. Think I may have an extra one in my sight box. No mystery metal all wood and steel. Frank
My 44 US has a small Ordnance wheel on the comb of the left side of the stock and my Rem 513 T has a RRA rebuild stamp on the left side toward the butt. I doubt the SF is for San Francisco even though at one time before it became a lunatic asylum there were “Normal” people there, most property was marked “City of San Francisco”.
I recall when my Father serviced the weapons at some schools, and units they would sometimes get commercial stuff to fix the weapons (usually replacement sights) that may not have gone thru the usual military channels,
(school had funds to buy parts outside of the .mil)
again, no way to really know with this particular rifle, just an observation
the stock and front sight isn't your typical configuration that M44 were issued with to military units. just a guess, it was probably put on for military marksmanship competition. the S.F. could mean almost anything, the A7 is more likely a rack number
The 144US and 144LSA are ones I don't have yet The 144US was a training rifle while 144, 144LS (stands for Lyman Sight), 144LSA & 144LSB were civilian target rifles. As mentioned earlier this is probably a rack number. I have seen this one discussed on another forum but don't remember the outcome,