Among the artists are some just starting out, who haven't developed the styles we recognize from the Marvel Age. Dr. Michael J. Vassallo has tracked Gene Colan's Timely work, for instance, to the artist's first stories, by working backwards month by month from his earliest signed work later in the Fifties—Colan's style is just the tiniest bit different a month before, and just a tiny bit more different the month before that, until at last it would be just about unrecognizable around 1948 if one didn't follow it step by step through the increments of change.
But Don Perlin's style seems to have sprung forth fully grown, as if from the brow of Zeus. This page is from "He Dreamt of Doom." So far I've looked at only the first two years of the crime books; they're something of a chore to go through before the scripts and arts become more appealing.
The Grand Comics Database has Perlin doing two one-page pieces in Western Winners 6 (Aug/49), but there I must confess I can't see him. When most of the artists start signing their work, Perlin does too; for instance, he has a story in Marvel Tales 110 (Dec/52) signed with inker Abe Simons.
UPDATE: Per Doc V.'s comment, I've dropped the other two stories ("Her Night of Peril" in Lawbreakers Always Lose 8 and "The Witch's Son" in Marvel Tales 96) that I'd listed here originally. I let myself see something Perlinesque in one or two panels in those, but I think "He Dreamt of Doom" shows Perlin in every panel.
early Don Perlin at Timely:
All True Crime Cases
|Sept/49||35||He Dreamt of Doom|