(edit) Well, there's a 300-dton Frontier Trader in 1248_Starships_1 (including deck plan). But it's not quite the same. I think the one in the Players Manual looks more like a 100 or 200 dton ship. I always saw it as more like a Beowulf.
It might be the 400 ton Solomani Sundowner Class Free Trader (see CT:Alien Module 6 - Solomani and DGP Aliens Volume 2: Solomani & Aslan (where it first gets its class-name)).
"Free Trader (type SA): Using a 400-ton hull, the type SA Free Trader is a moderate-sized ship designed for small-time merchant operations. It mounts jump drive-D, maneuver drive-D, and power plant-D, giving it a performance of 2G and jump-2. Fuel tankage of 100 tons supports the power plant and one jump-2. Adjacent to the bridge is a computer Model/1 bis. There are thirteen staterooms and no low berths. The ship has two hard-points, and two tons allocated to fire control; no weapons are installed. The ship has one 20-ton launch mounted in the nose of the ship. The cargo hold carries 160 tons. The ship is streamlined.
The ship requires a basic crew of five: pilot, navigator, two engineers, and a steward/medic. Two gunners may be added if called for. One of the engineers is assigned to pilot the launch. The ship can carry eight high or middle passengers. The free trader costs MCr133.4 (including 10% discount for standard design) and takes 14 months to construct."
[Posted under Fair Use Policy from CT AM 06 Solomani]
What is interesting about the 400 ton Solomani is that bulge in the nose is a 20 dTon Launch that separates [if you read the description].
So the MT RM image could be a non-Solomani variant without the Launch.