In J. Stevens Arms & Tool Co. Catalog No. 51 where the No. 350 was introduced it wasn't an engraved gun --
The same gun with Twist tubes screwed into the mono-bloc was the No. 360 and with Damascus tubes the No. 370 --
By Catalog No. 52 they added a No. 380 with Krupp tubes screwed into the mono-bloc. I suspect this was a special No. 350 for a Sportsmen's Show or Exhibition.
Very soon J. Stevens Arms & Tool Co. dropped the mono-bloc barrels and went to their demi-bloc (chopper lump) barrels --
They issued a special Demi-Bloc shotguns Catalog and by General Catalog No. 52 (Revised Edition), and the guns became the No. 355 with Stevens Compressed Forged High Pressure Steel barrels --
the No. 365 with Krupp Fluid Steel barrels --
the No. 375 with Krupp barrels and some engraving --
and the No. 385 with Krupp barrels and more engraving --
By the last J. Stevens Arms & Tool Co. catalog, No. 54, these engraved and rotary bolted doubles had been dropped from the offerings.