Savage employs found some left over parts and put it together.
Possible... maybe they had a finished and checkered 99T stock, and they sorted through receivers until they found one to fit. Otherwise they'd have had to set up for doing 99T checkering, odd if they'd done it for just a couple guns. Or not?
One would have to assume that it’s a put together rifle.
Last mention of the 99T on catalogs or pricelists I think was on the November, 1940 price list.
By January 1941 and the #75 catalog they only listed the 99G, 99EG, 99R/99RS.
By January 1942 and the #76 catalog they only listed the 99EG, 99R/99RS.
So leftover parts is the logical answer.