Agreed that single seater P-38s were used in 1944 as you describe. But there are a number of sources that refer to 2 P-38F/G conversions in SWPA equipped with SCR-540 radar complete with arrowhead aerial on the nose in early 1943. I don't have photos to hand but for example, Joe Baugher makes reference in his P-38M page.
And this Modelling site makes reference to entries in a number of books/magazine articles some of which had photos and includes some quotes and references to photos.
Anyone got Queen of the Skies to verify the quotes and photos?
23 & 515 squadrons RAF received ASH equipped Mosquito VI in Oct/Nov 1944 which they flew until the end of the war. It also went into Firefly NF.I from mid-1944. But, AIUI, ASH in the night fighter role lacked some of the features of AN/APS-6 (e.g. the blind fire capability).