I disagree with Jerry, Norme, and Wylon...They are basing their beliefs on Luger collectors, which is pretty much who they know on this (and other) Forums...and maybe a big show they frequent...And it is conditional on there being someone who wants that magazine/holster and is willing to pay your price *right now*...
Trying to sell magazines, holsters, accessories locally is a much more difficult task...Especially if you are trying to recoup money needed somewhere else...I know my local gunshops wouldn't want them, and CraigsList, Swap Sheet, etc isn't a reliable source for sales...eBay is always a good bet, but again, there has to be someone looking for that particular item...
IF you recoup your 'investment', you may have to wait some time for it...As everyone else may have all the magazines/holsters they presently need, and don't want to buy one for stock...
So I don't plan on selling any accouterments to try to justify my purchases...It is what it is, a $1000 handgun...If you can live with that, then you are good to go...
(That is my $.02 worth and worth every penny) 