Wecome aboard, Ogtree! I'm just going to copy excerpts from the HSc research booklet that Peter Theodore and I authored to answer your questions:
"Referring to the reported serial numbers, the end of M1934 production (serial number 628585) can, more than likely, be delineated between HSc 708708 (first HSc with the large Eagle/655) and 710508 (last reported small Eagle/655) or about March, 1941. Also, the elimination of the Army Test Proof was not a clean break as some non-test proof pistols have been identified as early as 712208 and others with the ATP mark reach up to 715323."
"Mauser made a few HSc pistols using phosphate finishing in combination with plastic grips in the early months of 1944, probably to demonstrate the concept to their customers in the military and police as an alternative to the more expensive and less resilient bluing process. The first documented HSc with these characteristics was serial number 882447.
882447 - Army (January 1944) 894194 - Army (March 1944)
891120 - Police (February 1944) 896889 - Police (April 1944)
By February 1945, Mauser modified their HSc production to include phosphate finishing as a wartime expediency. Much of the subsequent output that year, beginning with 946887 - Army, exhibited this coating."
I have no record of HSc's with inverted serial numbers. There were a few in the 950300 range with inverted Army Acceptance Marks. Hope that information helps with your lecture. Anything else, let me know.