Hello Leendert and Stig,
Thank you so much for your participation and help.
I have looked at the losses on the above site as well as here
https://www.aviationarchaeology.com/src/USN/PV.htm
PV-1 BuNo 49525 (81) - MSN 237-6341 - VB-136 - Landed in Petropavlovsk - 128 SAD (?) - found at a\f Kataoka
It can be: 49654 or 48733 ? or from interned aircraft 49472, 33278, 48909, 48930, 48910
Perhaps this is one of the interned aircraft, but none of them has the tail number "30" marked (perhaps the number was changed during the service, was painted over, but is now exposed).
As I understand it, in the USN loss reports, the engine numbers are not specified... BuNo could not be found.