The P-61A's first showed up in Europe around May 1944, about a month after first showing up in the Pacific theater. The first aircraft were painted in standard OD green over neutral grey. Early versions of the aircraft were fitted with a translucent radome.
I've built the Monogram kit several times over the years and though it is a good representation of the aircraft, it is at some 40 years old, a product of its time.
Great Wall a couple of years back produced a new kit of the P-61. While Monogram,s kit combines both the A and the B model into a single kit, and does it well, GWH produced three kits to depict the A with and without the dorsal turret and a third to do the B model. Kit L4802 is without the dorsal and comes with a non translucent radome. As you may already know, the first 37 P-61A's were fitted with a dorsal turret witted with 4 .50 caliber machine guns. When the turret was turned in flight it cased serious buffeting and there was a lot of issues trying to work the issue out. So Northrop deleted the turret from the remainder of the A model builds. The turret would come and go in various forms throughout the history of the aircraft. The first aircraft came with a translucent radome, how many were built as such I have never seen an information on, but they continued to be turned out this way even after the first 37.
Kits World "War Birds" series KW148169, has a turretless translucent radomed aircraft, 25534, Shoo Shoo Baby, based at Chateaudun, France late in 1944. Painted in the original OD green over neutral grey. I am taking the clear radome from kit L4806 for this build.