Here's a wool (or wool blend) long underwear set from the 1940s. These are US military issue. The top is long sleeve and pullover. We found these in
Military long underwear - Gem
NOS WW2 40s US Army Long Johns Drawers Underwear Sz 34 Under
Military Special Ops Long Underwear Layer 1 Silk weig… - Gem
VINTAGE Military issue Long Johns w/ Brace Tapes. button front and adjustable. Cream/Natural - Fogey Unlimited
Vintage WWI/WW II Men's Long Underwear Drawers Button Front Lace
WW2 German Army Thermal Underwear Long Johns White
40s Pre WW2 Wool Long Underwear LaceUp Button Fly Long Johns
Military/Landgirl 1940s 100% Wool Vintage Clothing for Men for
VINTAGE Military issue Long Johns w/ Brace Tapes. button front and adjustable. Cream/Natural - Fogey Unlimited
Military Long Johns