This is a really confusing topic due to the way the Catalog 90 developed, a particular copy may or may not have the FL9 depending on the vintage of the book. When the parts catalog was originally issued in 1950 (first edition) the F9, FP9, and FL9 did not exist yet. When it was re-issued in 1965 (the real second edition, but usually not marked as such), they all existed but some items pertaining to the FL9 did not make it into all the printings. There were numerous page modifications sent out for the post-bound early versions of the parts books over the years, and how complete a set of the books is, depends on who was maintaining them and whether the updated pages were all received and installed. Then there have been more recent reprintings, including some in glue bound volumes rather than the original post bindings. One of the most recent still lacks the FL9 carbody structure, side panels, and other carbody parts. It has the switcher two axle flexicoil truck and the SD three axle flexicoil truck, but there is no information identified for the FL9 trucks.
And, there also was a FL9 specific parts book which is a "supplement" to the Catalog 90 (just as there was an FL9 supplement to the F9 operators manual) and included primarily the items which differed from the other F-units, as far as I know it was issued only on the New Haven Railroad.
Rail Systems Inc. (RSI) of Houma, Louisiana still distributes the Catalog 90 for EMD.