i have taken them off to add Tone's sidemarker kit and install bulbs. the side marker is one piece (lens and housing).
don't know how you could separate them, to add the clear lens only. i suppose someone could figure a way to do it. however, i'd be concerned with getting it right.
i was tempted to purchase Ron's, when available. unfortunately, there was an issue with separation of the lens and housing and he has made them unavailable till he got it right.
$50 seemed low. that's probably fair for the lens, if one is willing to pay that amount. their new price reflects the 'whole' piece. with the amount of orders, he may reconsider the price. who knows.
-jose