That's interesting! Switch definitely looks to operate as CWE (as shown on relay) instead of OWE as indicated on the schematic.

I assume that the 50k relay just momentarily energizes when 50k is awarded on Horse Shoes (that's how it works on my 1953 Times Square at least). If so, it then makes sense that the switch should be CWE as this would cause the lites under the plastics to flash on when 50k is awarded (and emulate the bucking of the horses as shown on the playfield near the plastics). And so perhaps the error is with the schematic and not the switch. Otherwise, if the switch should be OWE, then the lites would flash off when 50k is scored (and perhaps also emulate bucking...?). Perhaps other Horse Shoes owners will chime in about how their plastics' lites operate.

Good luck!