HSRP Number plate for pre-2019 vehicles

Basically the title, does anybody know where to get one? I asked in RTO, they said search for HSRP website there would be one for Maharashtra specifically, order from them, and get it fitted by any local garage. I found too many websites, for other states as well as Maharashtra specific. Has anybody got there pre-2019 vehicle fitted with new HSRP plates, if yes please guide how and where you got it from!