All wing mirrors for sidescreen TRs were an added option. When I bought my 1958 TR3A, I wanted to keep the price as low as I could ($2616.00) therefore I told the S-T dealer no white-walls, no wires, no wing mirrors. But that total included the tax and the DMV fee for the plate, windscreen washers ($15.00), overdrive ($150.00) and undercoating ($35.00) regretfully.
Most TR wing mirrors have a nice curve to the stem, but the style you show were (and still are) available.