I did a comparison of the P90s in the 2008 '56 Gold Top with the P90 Pros in the LP Special. Here's my take on them.
Well the P90s finally got their shot today and I can answer in a very superficial way that there is an audible difference between the older P90s in the 2008 Gold Top and the 2022 LP Special although it's more apparent soloing each pickup than when they're combined. Both guitars have all mahogany bodies and necks but different bridges/tail pieces.
Both guitar are set up about the same or as close as I can get them and the pickup heights are also much the same. Pretty much factory specs. Strings on both are D'Addario XLs but the Gold Top has 9.5-44 while the LP Special has 10-46 I believe. Not scientific caliber stuff here though.
While I always experienced those on the Gold Top P90s as having more clarity and being less gritty than their Gibson cousins they are a little bit grittier than the new P90 Pros which also seem to have more clarity and subtlety more depth and harmonics. I'd say they're "more refined".
These are very basic impressions of both run full up on volume and tone through my Blues Cube 60 playing clean in it's "Tweed" mode. I have always thought the Epi P90s were great pickups. I would call the P90 Pros a step more exceptional but again not a night vs day difference.
One more impression. If I want a guitar to play straight out rock that I can get nasty with or mellow out of just by a flip of the pickup selector I'd take the LP Special for that gig. In my world it is rock guitarists go to. The Gold Top I would lean more toward for blues or jazzier stuff.