while looking for info to ID spokes on an old French wheel, I came across this list in the CR archives:

Spoke Head Markings
Mark Brand Country Comment
DT DT Swiss Switzerland
U Union Germany
R (Reversed) Redaelli Italy
A Alpina Italy
Y Prym Germany
E Trois Etoiles France Robergel
Crescent Robergel France
Clover Berg-Union Switzerland
Star Stella Italy
W Wolber?
W Wheelsmith USA Since 1984 probably made by Asahi
P Performance probably made by Asahi
Three stars Trois Etoiles France Robergel
Three dots
Cross (+) Torrington USA (Connecticut)
A Asahi Japan
H Hoshi Japan
SAP Sapim Belgium stamped on the elbow
T (in shield) Torrington USA

I think John Hurley (who complied it) would not mind it being shared with our crowd