Not in my case, as the pickups are covered, so I'd have to unsolder the cover, remove wax, etc. I think a pot swap might just do the job.
Ok. I have Duncan Antiquitys in most of my guitars and they come stock with a roughcast alnico 2 magnet. If you want a vintage pickup the Antiquity has my favorite sound.
The cover is aged though. Might not match the look of your neck pickup.
Do you want another covered humbucker? The Seth Lover is very close to the Ant but it has a polished A2 magnet which gives it, IMO, a bit clearer and slightly less textured sound. Still an excellent sound and better than the 57 Classic, IMO.
I think I might just not be that much into vintage output humbuckers. They all sound brighter than overwound pickups. To my ears, the're even brighter than stuff like the JB or Distortion.
My Alnico II Pro Slash has a bit of the same problem, but by lowering the polepieces and especially the one on the high E, I solved much of the problem. Same with the '57 Plus, It sounds better now with the polepieces lowered. I still might need to throw a 500k volume in for the neck and maybe a 250k tone for the bridge. I think that will give me the desired sound.
I think the Traditionals of that era had 500k volumes and tones. Mine is a 2016 and it came with 500k for both volumes and tones. I wired them 50s style when I got them (and the prior owner had already replaced them with CTS pots but I have the originals -- I can measure them to be sure when I get home). Here are the specs:
http://legacy.gibson.com/Products/Electric-Guitars/2016/USA/Les-Paul-Traditional.aspx
I would start with pickup height honestly. Set them around Gibson specs -- about 4/64 (1/16) from the strings with the low and high E depressed. You might lower them a quarter to half turn from there, but that should thicken things up. If not, they just might not be the right pickups for you.
I prefer unpotted pickups for that PAF tone, which is what the 57s are after. In that light, the recommendation for Seth Lovers would be my next suggestion as well. I had Antiquities in mine that were fantastic (and I'm about to sell them) and I have the Custom Shop Pearly Gates set (unpotted, double creme) in there now. I prefer the latter, but any of those will get you in the ballpark and should thicken things up a fair amount at the cost of some low end "firmness." The PAF types have a more spongy low end, softer than a hotter, potted wind with an A5 pickup. If you want to go the other direction and firm up the low end while getting more bite, Duncan 59s would do the trick, or you could use a hotter bridge like the JB or Custom. I have a JB/59 set in my other Les Paul now and it sounds amazing.
Changing the magnet in each pickup from a polished alnico 2, to a rough cast alnico 2 will also thicken the sound.
It's an easy thing to do with uncovered pickups but harder if the pickups are covered, as the covers will need to be removed and then put back on again.
I don't know if the 57 Classics are wax potted or not. Duncan Seth Lovers and Antiquitys are not.