Sounds like you're trying to convince yourself or others that your car is "rarer" than it is.
per GG's "white book" (should be fairly accurate ) built to US specs:

1970 Barracuda convertibles with 383 2bbl (automatic only) BH27L0B = 59
1970 Barracuda convertibles with 383 4bbl (automatic) BH27N0B = 36
1970 Barracuda convertibles with 383 4bbl (4-speed) BH27N0B = 17
1970 Barracuda convertibles with 383 4bbl (3-speed) BH27N0B = 6
also:
1970 Barracuda Gran Coupe convertibles with 383 2bbl (automatic only) BP27L0B = 54
1970 Barracuda Gran Coupe convertibles with 383 4bbl (automatic) BP27N0B = 66
1970 Barracuda Gran Coupe convertibles with 383 4bbl (4-speed) BP27N0B = 18
1970 Barracuda Gran Coupe convertibles with 383 4bbl (3-speed) BP27N0B = 2