Hi Joe - your friend might think that it's 1954 because that number (X926) looks like a Factory Order Number or "FON" and the letter prefix for 1954 was "X".
I have a '54ish ES 125 that so far most people I've asked think is a '54 cause the closest thing to a number that can be found on it is "X249".
Someone who knows more will probably show up soon.
You've probably already found this site but if not:
Vintage Guitars Info - Gibson
August 1942 LG-1 introduction specs:
14 1/8" wide Spruce top, X-bracing, mahogany back, no lengthwise center seam on inside back
mahogany sides, mahogany neck, rectangle bridge with black pins, single bound top and back
sometimes darker sunburst finish (darker than the LG-2, to hide the lower quality spruce top).
Only a Gibson is Good Enough" banner logo. Only about 100 made in 1942, production ceased until 1946.
In 1946 the "banner" is dropped (still a script "Gibson" peghead logo). Bracing changed to ladder.
In 1948 goes to a "block" Gibson peghead logo.
In 1955 larger pickguard with point, and 20 frets total.
In 1962 plastic upper belly bridge. $105 list price.
In 1966 rosewood bridge with adjustable saddle was used.
Discontinued in 1968 but seen as late as 1974.