Gotta say, what part of the welding do you mean specifically? Because here for example is the welding of a P3SL Cervelo (aluminium), which once upon a time was a top TT frame:
The welds on the Pinarello look maybe a tiny bit irregular in one or two spots, but it's not really that bad.
Professional rider's bike Pinarello Banesto 1997:
Link to ebay deleted , against the rules , sorry !