Well that is the question now isn't it? Is it something to consider or not? I take it from your response that you are in the camp of it doesn't matter how it's made, they are all the same?
I have meerschaum pipes with a variety of fittings. I have a couple that have a screw in, metal stinger style, and plastic screw in, many that are the common push/pull tenon, and some that use the briar style tenon/mortise setup. All my meers smoke good to great and I can pass a pipe cleaner through all but two (metal stinger prevents it). I buy my meers for the look and deal with whatever fitting it has.