NFC isn't software, it's hardware, you need a chip and an antenna. I haven't seen a 935 disassembly but I reckon the hunnymonster has the chances about right of it having NFC
If you're desperate for contactless payment on your watch and it has a 22mm strap - a bPay loop would do it (without looking too hard I've found them retailing for as little as GBP12)