Reinstall RouterOS after OpenWRT

I’d like to know, is it possible to reinstall routeros after having openwrt written to nvram, with the old licence key I exported. Or do I have to buy a new licence?
Board is 433UAH, v4.6,

If anyone has any experience, please reply!

Thanks!

There should be the same license (software-id) after you reinstall RouterBOARD with Netinstall.