Possibly not able to do what you suggest greasytech.Boeing filter kits (65-90305-xx) come all packaged as a unit with only 1 GRN.If you only needed 1 filter but the kit had 2,the remainder you were left with would be an incomplete kit and I do not know of any storeman whowould accept that under the original GRN. My belief is that you would have to go down the road of recertifying every item left individually, filter, o-rings etc. and we all know what fun that is! Far easier, quicker, better to file them in the big round file!!
On a different note greasytech, did you see a big orange advert in the local press/flight international? Come on in , the waters fine!!!