Top kit is the Revell (developed by Revell of Los Angeles in 1980) of Germany kit. It is a full glue kit. Cummins 475 in-line 6 engine, 1981 Peterbilt 359S19 - a Peterbilt model 359, steel frame, 119" bumper to back of cab (BBC) length. 63" sleeper. Dual air cleaners.
The bottom kit is the Monogram (later branded as Revell) kit. It was developed as a snap-together kit. The cab and sleeper are molded as one. The sleeper is the smaller 36" size. Single air cleaner. Caterpillar in-line engine. 1982 359S19.

Differences: Snap kit has no cab visor, proportions on some items are a bit simple or distorted (battery/tool box, odd step on fuel tanks, oversize underchassis air tanks, simplified suspension). The snap has smaller fuel tanks. The glue kit has large diameter fuel tanks, optional roof mounted Varshield air deflector.
Both kits are the same era - 1979-1983. Both kits have the Dash of Class instrument panel (trucker slang "corvette dash" which is a misnomer but that's a different topic). Both kits have Classic II interior, VIP optional steering wheel, both have rectangular headlamps (production available on the real truck after '79) - you can see the difference in the level of detail between the two kits in the fine detail of the headlamps on the glue kit. The snap kit has a not-so-common long end-of-frame overhang.

Both can be built to a fine representation of a Peterbilt 359. The snap kit has a nice stance when finished but out of the box but doesn't look as "complete" as the Revell glue kit. You can mix-n-match parts from the AMT Peterbilt 359 Wrecker (and CrossCountryHauler coming later) but the parts are not direct fit between the AMT, Monogram or Revell and will need trimming or slight modifications. The three companies had completely different solutions to assembly, wheel attachment and tire compounds (the Revell (both kits) have issues with the material the tires are molded from, either too soft and go flat sitting on the shelf or turn chalky grey over time.

The Revell glue kit is much more involved with opening cab doors and plenty of interior detail. the snap kit has much fewer parts.

Tim