I would say you are right on which fits the portacatena. The bottle bosses were most likely added when it was painted as this fits 77'-79'. And the decals may not be original, for a few years,until about 79' they had the "D" in the heart on the head tube. Then a few years without but in the same position. After that they were 45-90degrees out so the second bottle would not cover them. The transition to castlugs was late 79' or 80' and the seat post clamp swooped up on those. There is also some info out there that states 80' had the star on the inside of the fork. Your fork appears to be the earlier than 80' due to that and the heart only, not stamped "De Rosa". 77' had some examples using clamp on brake cable guides and decal differences in some instances. The heart on the back of the BB was typical late 70's. Bottom bracket will probablyhave two slots if pre-80, 79-80' may have like 4 or 6 squares. Can't recall exactly. Might tell you if it's closer to 80' or 78'.
Last edited by Bikerider007; 02-13-17 at 02:01 PM.