What glider types can be retrofitted with a 'nose' tow hook? Whatglider types cannot?

I got a quote from Blanik America in June of 2012 of $1800 for a factory authorized complete kit-of-parts to add a nose hook to an L33.

I did not get a quote for installation labor. The L33 is a metal glider and perhaps that would make the installation less labor intensive. Does anyone know the labor cost for adding the nose hook to the L33 (to complete the picture)?

The L33 glider in question had about 200 hours on it and the price was in the low 20Ks. I would have spent the money on the nose hook if I had gone forward with the purchase, but I found a better 'first glider' that also happened to have a nose hook. The lack of the L33 nose hook was the only reason that I delayed the purchase until something better came along. At the time I was infatuated with the L33 and the money was 'burning a hole in my pocket'.