[VAL] question on old propane tanks

[Jerry7820@xxxxxxx]

someone told me that if you did not have a OPD valve on your tanks no one 
will fill them

is this a true statement ???????????

what year did they require the OPD valve and what do they look like  ?????????

can the cut off assemble be replace with a OPD valve without buying new tanks

this is a 1970 tradewind and someone may have replace the tanks ??????

anything would be helpful

jerry