Some sources say actual production ended in 1935, with s/n 708259 at the start of the year and 25 made that year, so that would make the last number 708284. In any case, they had enough unnumbered receivers and parts to assemble and ship guns for several years after that. Supposedly serial numbers reached 848000, (we know they reached 803,xxx) but there were gaps and actual production reached only the 708,284 or so indicated in the books.
Why the gap(s)? I don't know but I suspect they lost track of where they were when production stopped and when they assembled rifles they jumped ahead far enough to be sure there was no overlap.
It might be the light or the photography, but the rifle shown by Quadvet appears to have been reblued.