Richard, oh my, brakes
mine field here, many were dual braked from the mid 60s, but not all of the class were dual braked, some remained vacuum braked to the very end. Some locos were dual braked and then in the last years reverted back to vacuum only.
So yes, you can have an air braked green with small yellow panel and pre tops numbers, in 1970 there were 85 dual braked locos, in 73 there were 120, but not necessarily the same from 71 unless they are typos. By 1980 it had risen to 123 and that's probably near the maximum ever achieved as they were on the run down by then.
Do you have a rough date or numbers you want, I can check them off, a quick scan through the digital collection shows D213 with small yellow panel at Kingmoor as late as 1968, but there's full yellow panel locos as early as 66-67, your best bet is one from the 1970 list, I'm afraid I don't have dates for dual brake fitting, though I suspect it must be out there somewhere