Call Rossi and ask for a manual
You will have to call Rossi with the serial number to find out.
You will have to contact Rossi
A Sears Moels 300 is a Winchester Model 1400. For a manual, go here: http://www.stevespages.com/page7b.htm For disassembly instructions, get a copy of Gun Digest Assembly/Disassembly for shotguns. Aslo, gunpartscorp.com has an on-line exploded diagram for the model 1400.
You will have to call Rossi to find out.
midwayusa.com, search under Charles Daly
The Gun Digest Book Firearms Assembly and Disassembly Part 5 Shotguns has an illustrated description of the model 97 disassembly.
Contact Marlin.
Not marked AFAIK
Check the diagram on Numrich website or in their book. egunparts.com The original manufacturer for your gun is High Standard model K2011.
You will have to find old Rossi catalogs or call Rossi to find out unless you have the box. If you do, it should be marked.
Rifle, handgun or shotgun?
No