Trying to use Mame 2003 Plus RetroArch Core, but not listed?

[BlockABoots]

So im trying to use the RetroArch core, 'Mame 2003 Plus', i have selected the option to 'Import MAME Arcade Games (Full Set)', pointed it towards where my full 'MAME 2003 PLus' roms are and selected RetroArch as the emulator.  But when i click on the 'Associated Platforms' tab there is no MAME or even Arcade core available to select let alone the 'MAME 2003 Plus' core i have in my RetroArch 'Core' folder. Can anyone help?

[DOS76]

Arcade is one that you have to add on your own once you add it in the Associated Platform column then the core column will be a drop down menu as long as you have the core downloaded through Retroarch then it should show up as an option in the drop down list.

[BlockABoots]

Ok thanks, ill give that a go. Odd that is not already populated though

[Lordmonkus]

4 hours ago, BlockABoots said:

i have selected the option to 'Import MAME Arcade Games (Full Set)'

This is for an up to date rom set, not the older sets such as the 2003 set.