Finding
decals for a Yak-1b is not difficult. Several manufacturers either have
dedicated sheets to the later Yak-1 or have them included in a sheet of
generic Soviet fighters. What is less easy is finding a sheet that has the
earlier Yak-1 without the bubble canopy. Fortunately, Foxbot decals out of
Ukraine produces this nice set that includes all the earlier versions. What
is really nice is that it has a nice selection of the early variant with the
large section of rear plexiglas. 
First
up is one of those early types in an overall winter white over the usual
light blue. It is of the 562 fighter regiment in the defense of Moscow
during the winter of 1941. This one is shown with skis. Next is another white over light blue plane, this time with the 21st fighter regiment based near the Baltic in the winter of 1942.
The third option is an overall green over light blue plane of the 273rd fighter regiment in the Kharkiv region during 1942
The fourth is a later version with the 28th fighter regiment during the summer of 1942. This one has the later camouflage scheme that added black to the upper green.
Fifth up is a well worn winter camouflage scheme of the 123rd fighter regiment. It operated near Lake Ladoga near the Finnish border.
Finally, a later option that operated near Stalingrad in late 1942. It is in the then standard green/black over light blue scheme.
The sheet is nicely printed and not only offers all the markings for the above mentioned aircraft, but also a nice selection of aircraft numbers in case you wanted to do something different. Stencils are provided and you have enough insignia for up to four aircraft.
To my knowledge, in 1/48 scale, only the Accurate Miniatures kit is available. This has probably been reboxed by others.