The marking says a 1600 1969 spider. That might be for the 1750, but more probably modeled to fit the 1967 Duetto. Remember Alfa did not import in 1968, and if the tag says 1600 and a 1969 it may just have been sold late the year after sitting during the off year.
This is from an add that appeared on Car and Classic.co.uk
Giulia/Giulietta Spider Hard Top (101) For Sale
Very rare hard top to fit 59-63 Giulia/Giulietta 101 spider. Manufactured by Dynaplastics of California as part of their 'Royal Coachmen' line. The roof is of GRP construction, with a glass window and is in good condition, however would benefit from refurbishment. These roofs are very rare and hard to find. £800 ovno, collect only
Oops, I looked more closely at the "step down" at the rear edge of the door opening, and realize that I am TOTALLY WRONG in suggesting this a Duetto top. Not so at all. It fits the earlier models. In Seattle we used to have a business called Thomsons Hard Tops for us exposed to the endless winter rain, but not only for Alfas, but for all the small sport cars in the late 50's and early 60's. And I once purchased two plastic hard tops from Parish Plastics for my two liter -- selling one to some other half drowned native here, and then when I finally got a factory top sending mine on the way too. But the choice hard tops are still the ones made by the factories which made the original cars. I recall a factory hard top on the Giulia veloce that Jack Brooks had. It got too small for his family, and I suspect he still misses it. For many of us the song is "I wonder who's kissing her now?"
I'm pretty sure it IS a 101 hardtop of fiberglass. These were available in the 1965 onward period when some were driving the spiders year around, and factory steel PF tops were no longer available from alfa or dealers. Even in prime condition, these are not valued by 101 spider owners.