The 13-61 project ended - as you say - in 1952, but the Tipo 103 prototype is on display in Museo Storico with the year "1954" (see below) on the info board. It also says "896 ccm 4 cilindri monoblocco", which is very different from project 13-61's 2-cyl "half twincam". The engine for the 103 project was in fact a whole new engine (and not, as I said above, a small-bore alu Twincam). The latter is also on display in the museum next to the Tipo 103 car.
I looked it up in the Fusi book: the Tipo 103 prototype was according to him finished in 1959. The info board in the museum is probably wrong
. Imagine that
So, you are correct in your (?) article! Looks like you can never consult enough sources on Alfa Romeo ...
Failing to mention Hruska is still in it though. Hruska was also on the Porsche 360 design team in the late 40's, as well as on the team who designed the infamous German WWII Tiger Tank.