@mrplow no problem!
The used low-profile nuts in the kit are M3 DIN934 - the height (i just measured) is 2.3mm - 2.4mm with a standard M3 thread - i believe your linked product on Mouser would work regarding the dimensions and thread, but it is nylon material - which is not recommended. The SEQ v4+ kit contains stainless steel (A2) variant nuts. Maybe you can find a retailer that has the european M3 DIN934? It’s quite a standard over here, but then there’s always the dispute of the measurement systems (imperial vs metric), so i hope you can find it in the U.S.!
Best regards and have happy holidays!