As has been said. If it has a 250 engine it is a 250 plain and simple. The 300 was a more powerful engine and I can't imagine having a 250 engine lying around that they would rather have in a Urraco vs the 300 lump.
Very neat cars either way. The 250 is probably more available as the 300 is scarse.
What is the condition like? Photos?

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