I make resin copies of both these wings in my spare time. The quality is not as good as BTS, as my moulds and casts are all hand prepared and poured, but are still quite good copies of the originals, (although being resin, they are not as strong.
If you can't get them anywhere else and/or they are too expensive, I only charge between $2 and $3 (AUS) each, depending on whether you want them cast in plain white, or tinted. The advantage of tinted resin is that the colour goes right through, but I can't guarantee a perfect match, and you can't paint over them once tinted (the pigment seems to react with paint, no matter what you do to set or seal them).
However, your biggest expense will be postage, which is getting quite exy these days, about $15 to UK if I remember correctly. But I do tyres and lots of other parts as well for this vintage of cars, so if you can order enough parts, it generally becomes worthwhile.
Feel free to pm me for more info if you want.