Maybe. I hear an uncovered pickup as having more presence...the highs seem to spray out of it. (I know that's not what actually happens, that's just a way of describing it) I think with a nickel cover the pickups sounds a little warmer and in a way more focused. The diff is very subtle to some players and very obvious to others! Guess we all hear what we want to hear. Lew
I've always played Les Pauls with covered humbuckers and have in the last few months for the first time used open humbuckers. I bought a Gibson Les Paul Classic with the stock "hot" ceramics but have changed them a few weeks ago for SD 59's open coil alnicos.
There is a distinct difference. Indeed there is more open treble content and a sharper sound with open coils but far more significant for me with the open SD 59's is their susceptibility to noise.
On high gain I get a distinct buzz with SD 59's that goes away when I touch the strings - I didn't get this with covered Gibson bustbuckers. Also the pups seem more prone to knocks and clunks with the pick than covered pups do.
However, the tone of the open SD 59s is superior without doubt...now if I could only get rid of that damn buzz.
Remember that the 59's are Alnico V and the Burstbuckers are Alnico II. Alnico V pickups will usually be a bit toppier than their Alnico II counterparts, this, along with the lack of covers, might be what you are hearing iin your LP.
other pickups to look at are a tele neck pickup, and the phat cats. they have covers and that reduces some hum, so even on the humbuckers it has to have some effect on the tone but i do not have two guitars to a/b open and covered pickups.