That one could be lettered, the serial number is low enough. I don't think it would be a Spiegle gun without the engraving, but there could be other mfr's that Savage worked with. We've seen other guns including R's with those d&t holes as well, no idea who did them.

“The Savage 99 Pocket Reference”.
All models and variations of 1895’s, 1899’s and 99’s covered.
Also dates, checkering, engraving.. Find at www.savagelevers.com