"Muffled/Muddy" sound from L1290/2's?..looking for solutions, please!

[eyespy18]

I'm no expert, but I feel that my original, unrepaired pair of L1290/2's sound a bit muffled, or muddy, overall and especially in the midrange. (I've always loved them but I may have changed my hearing perspective by listening, with the same source, a pair of granted VERY different sounding B+W 702s2's..ultra clarity). FWIW, not crazy apt the B+W's... Anyhow, do you think it's likely time to have Richard rebuild the tweets and mids and opinions welcome on the likely benefit to doing so. The same question would apply to having the xovers rebuilt and would love opinions as to whether those rebuilds might open the sound a bit. My naive, uninformed sense says "well, there *are * over(?) 40 years old ( and not always stored in the best, ie:HOT environment. Your more learned and experiences most welcome! FWIW, I'm powering them with a Marantz SR6015.Thanks in advance!!