But you have full knowledge of all maintenance done in your ownership. Walking into old motors without knowing what has been done, and what general level of care taken, that's a different story. Not saying it's an automatic repower, but there are systems there that have to be viewed as suspect, and budget allocated for remediation or replacement.
If I was buying something like this, I'd plan to do a major service on both units, regardless of what the seller says has been done. Then I know 100% certain what state things are in going forward. Spark plugs, water pump replacement, oil and fuel filters, carb clean/rebuild, leg oil. Fuel pump tests, possible rebuild. And replace all fuel lines in the hull.
Twins means all parts and labour x2. Definitely points toward DIY if possible. Even if everything checks out and they run well, needs a substantial price reduction to provide some cushion against all this baseline work needed for them to be reliable power for a new owner.