Did I make a poor purchase?

[Darreld Walton]

read, think in Brophy, earliest A4's used off shelf 330's before marked M73B1 models available. only steel tube sturdiest available at time. need opinion experts?

I don't think Ordnance went out and specified the 330 because it was the best, or ideal, or what was really wanted. More likely, it was the only thing available in quantities they could use, and wrote the spec to meet that model.
Truth be told, the 330 is a pretty pathetic piece of glass, and wasn't the 'best' by any stretch in 1943!