Definitely NOT a '79...
Thank you all for your replies. The owner of the yard called me today and informed me that the X1/9 is actually a 1979 model...
As others here have already stated, this
is most likely a '75 model. Proof of that would be the
1975-only front turn lamps with black plastic base "extension" housings ('74 had the same lamps, but bolted directly to the car body). More proof that it's not a '79 are the ladder-style bumpers (1975-78), the targa vent covers with the early cast-in "bertone" logo, the early-style engine lid & side vents/trim, the early "X19" rear trunklid emblem, & the all-red (not amber) rear turn-signal lenses. This car
might also have the '74-style manual choke knob next to the emergency brake handle (along with the '74-style black plastic e-brake/choke console/surround).
All it takes to verify the year is to open the drivers door & look at the white plastic year/VIN ID tag on the lower B-post. It may have a late-'74 year on that tag, which the junkyard staff may have accidentally copied down on paper as "1979", or maybe they did write "1974", but have bad penmanship? (I had this exact thing happen on a '74 x I had a long time ago).
I asked about the distributor setup (points/electronic?) but he didn't have time to look. My question to all : If it truly is a 1979 model, will it have the electronic ignition setup or points system>?
A '75 model would normally have the Ducellier points-type distributor, though there is the possibility of a previous owner having replaced it with a Marelli points-type distributor from the 128. It would not normally have an EI type distributor setup unless a previous owner had installed that upgrade him/herself (ie: either an aftermarket kit, the late X1/9 Bosch setup or the Yugo Bosch setup).
A '79 model
should have the Bosch electronic ignition distributor setup, as that was what was factory-installed on that car. This
can be swapped onto the 128, though you may have to lengthen some of the wiring on it depending on your installation.