thanks for the info but I just checked my es_systems.cfg file but there are no platform ID numbers – for Vectrex or any other systems either.

here is the entry for Vectrex

<extension>.vec .gam .bin .zip .VEC .GAM .BIN .ZIP</extension>
<command>/opt/retropie/supplementary/runcommand/runcommand.sh 0 _SYS_ vectrex %ROM%</command>

and here is the entry for SNES

<fullname>Super Nintendo</fullname>
<extension>.bin .smc .sfc .fig .swc .mgd .zip .BIN .SMC .SFC .FIG .SWC .MGD .ZIP</extension>
<command>/opt/retropie/supplementary/runcommand/runcommand.sh 0 _SYS_ snes %ROM%</command>

they appear to both hold the same information.