Lt1 is not "rare", but certainly not as common as std motor. I would target have lt1 anyway if all things were equal. I'd rather have a good condition std engine boat that was taken care of than a trashed lt1 boat. Bottom line, it is a plus, but not a huge premium unless you must have the extra power.
That does seem like a good deal. I think that boat was for sale a year or two ago w a trashed interior. Which is likely why it is new now.
If the hull is good and engine checks out, I agree it is worth more than a good look, seeing how this is what you said you want.