Based on other Benotto 3000 that I have seen, I'd place this circa 1980-1981 and would be leaning towards the latter. We know it's no older than the 1978 model model year as it has the 1977 Camapione del Mondo decal celebrationg Moser's victory at San Cristobal on August 27. It also has what appears to be Portacatena dropouts, which were introduced in the fall of 1977 for the 1978 model year.
However, I believe we can eliminate 1978 as I have seen other model 3000 with Portacatena dropouts that had the derailleur cable routed over the BB shell. These would be no older than the 1978 model yearbased on the dropouts and since the OP's frame has cables routed over the BB shell, it should be newer.
Similarly, I believe we can eliminate 1979, as I've seen othe model 3000 with Portacatena dropouts and cables routed under the BB shell but with brakes calipers that use exposed brake nuts, unlike the OP's frame, which appears to use recessed nuts.
Finally, the 1982 model 3000 I've seen have used a brazed-on front derailleur hanger, while the OP's frame requires a traditonal clamp style front derailleur. So, the OP's frame would appear to be older than 1982.
That leaves 1980-1981. We may be able to increase our confidence level via the date codes on the rear derailleur, crankarms and hub lock nuts.