First of all, what does your system consist of Tubes, SS or a combo of both)? Your listening preferences (which will have a big effect on what your going to have to do)? Your room will with NO DOUBT effect what you hear in conjunction WITH your system as well as how it is apparreled (rugs, couch, wall hangings etc.)!
Second are you currently pleased with how your system/room sounds? If not I'd concentrate on that first. Your back wall is going to influence your sound with different types of reflections/absorbing. IMO the record covers will have a different type of reflection (if any) but, the grids will reflect and quite possibly cause all sorts of different new types of problems. If it were me I'd think a bit more about this as, without any further info it seems that you may end up spending a bunch of money needlessly to correct things that wouldn't have to at this point that could improve your listening enjoyment in the first place but, again this is just my opinion.
Second are you currently pleased with how your system/room sounds? If not I'd concentrate on that first. Your back wall is going to influence your sound with different types of reflections/absorbing. IMO the record covers will have a different type of reflection (if any) but, the grids will reflect and quite possibly cause all sorts of different new types of problems. If it were me I'd think a bit more about this as, without any further info it seems that you may end up spending a bunch of money needlessly to correct things that wouldn't have to at this point that could improve your listening enjoyment in the first place but, again this is just my opinion.