I have been studying the part numbers for various bikes and banshees. The first three letter numbers (31K) are the model number the part was first used on. The next 5 numbers are the type of part. The last two are a revision and should not be an indication that the part won't fit. 31K-15160-10 version is on the parts list for the 1984 onwards RZ350 and the 2009 YFZ350 Banshee. Some part numbers do not change even when it is a very different machine as the part itself was reused and was not redesigned. That is why you will see in the parts list for the 2009 Banshee prefixes 4L0, 29L, 31K etc even 278 which was from the earlier air cooled RD.
This is from the 2009 Banshee
1 4L0-16111-00-YX GEAR, PRIMARY DRIVE (23T)
2 90282-07023 KEY, STRAIGHT
3 90208-16019 WASHER, CONICAL SPRING
4 90170-16425 NUT
5 31K-16150-10 PRIMARY DRIVEN GEAR COMP.
6 1A0-16371-00 BOSS, CLUTCH
7 5Y1-16331-01 PLATE, FRICTION 2
8 498-16325-00 PLATE, CLUTCH 2
9 29L-16351-00 PLATE, PRESSURE 1
10 29L-16356-00 ROD, PUSH 1
11 90149-08143 SCREW
12 92907-08200 WASHER
13 95317-08700 NUT
14 90501-23138 SPRING, COMPRESSION
15 90159-06016 SCREW, WITH WASHER
16 360-16154-00 PLATE, THRUST 1
17 278-16367-00 RING, CUSHION
18 278-16181-01 SPACER 1
And this is from the 1984 RZ350
1 GEAR, PRIMARY DRIVE product number: 4L01611100
supersession: 4L01611100YX
2 KEY, STRAIGHT (584) product number: 9028207023
3 WASHER (517 CLUTCH) product number: 9020816019
4 NUT (8A0 CRANK) product number: 9017016182
5 PRIMARY DRIVEN GEAR COMP. product number: 31K1615010
6 O-RING (278) product number: 9321110232
7 BOSS, CLUTCH product number: 1A01637100
8 PLATE, FRICTION product number: 5Y11632101
9 PLATE, CLUTCH product number: 4981632500
10 PLATE, PRESSURE 1 product number: 29L1635100
11 ROD, PUSH product number: 29L1635600
12 SCREW (3R4) product number: 9014908143
13 YBS66-8 WASHER, PLAIN product number: 9299008200
14 NUT (1K7) product number: 9531108700
supersession: 9531708700
15 SPRING COMPRESSION168163330000 product number: 9050123138
16 SCREW, WITH WASHER (1W4) product number: 9015906016
17 PLATE, THRUST product number: 3601615400
18 RING, CUSHION product number: 2781636700
The nuts and bolts and washers are interesting as they are usually not model specific at all. The first 5 digits are the type and the last five are usually the dimensions except for some special parts. If you see 9015906016, that is a screw with a particular hex head and flange with diameter 6 and length 16 in millimeters.
I think the advice on the forum would be to replace the clutch basket with a mikata, removing the gear and plate and reusing these if not damaged. If they are damaged then the complete Banshee assembly would be the way to go.