301 redirecting a previously abused URL

[Salience_Search_Marketing]

A client previously had their most important landing page at domain.com/example.htm

They carried out the sort of link building that was commonplace a few years back (exact match anchors, paid blog links etc) targeting this URL, but they also got a bunch of legitimate decent quality links here. I believe they may have had a number of issues when link quality algo updates were rolled out, so rather than try and get links removed and go through the disavow process they instead decided to abandon this URL, let it 404 and start afresh at domain.com/example.html - updating all internal navigation, XML sitemaps etc.

So fast forward to today. What is the best practice for this URL these days do we think? Is it now possible to 301 domain.com/example.htm > domain.com/example.html and recover whatever value may be left here? The argument for not doing so may be that you could pass over the negative metrics associated with the old URL, but would this not be handled by the real-time penguin update and the poor links just devalued rather than actually harming? And could this just be tested - i.e. add in the 301, monitor the impact and if things don't go the way we'd want then just remove the 301 again?

Would be keen to get a few opinions on this.

TIA

[Tenlo]

The big question is how long ago did the URL change take place.  I have had similar circumstances when gaining new clients who had been working with some less then ethical companies and we found that after ~6 months there is little SEO value unless there are still good, active links pointing to those locations.  If there is still some good links pointing to the original location then you should regardless, but if not and it has been longer than 6 months I personally would not.