Those numbers don't mean anything to me other than the date code of 1977, so I don't know if the 2 replacements are correct or not. I would suggest that you replace the 4 outputs with the same number or same types. The generic part number is 2N3055, which you will find a lot cheaper than the NTE parts.
Which of the 6 transistors are bad, the RCA's, the replacements? There are 4 for the power amp and 2 for the low voltage power supply. If the 4 RCA's are good, use them in the power amp and replace the power supply transistors with new ones. If some of the RCA's are bad, replace the 4 power amp outputs with new ones and use any others in the power supplies. The power supplies do not need matching transistors, while it is best to use the same type transistors in the power amp section.