Ummm Blueberry wasn't ever introduced to the public until 1995 in Amsterdam first, After DJ Short took his work with him and was prompty ripped off by Sagarmatha and That piece of **** Henk from Dutch Passion
who still exploit his work today with no compensation to DJ...
So the claim by your buddy is bogus,,,I was growing back in 1983 and forward and can tell you NO blueberry was available nor ever heard of in the eighties or early 90's....
Your cut displays the typical DP type bud structure but the fan leaves are lacking the typical spear shape they have as a classic sign,and surprisingly you have 0 shades of maroon or purple,you should at this stage,but it's not a guarantee.... I'm sure the smoke is pretty decent though.
Good job on growing them out,nice yield...