You had only 2 regiments with this skull and crossed bones plate..... and 12 with the Prussian waved bandeau,
You should then find 6 times more this normal type than the LH type.... now, look at the private collections and museums ! So many LH busbies !!!!!! It's even more difficult to find a Prussian busby than a LH..... As I'm French

))))) I would try explaining this phenomemon by comparing with women .... did you realize how many blonde girls you see compared with blonde men ?

.......... Normally, there should be the same proportion !
well, concerning busbies, a LH is more sexy than a Prussian one, and this since the war itself ! Therefore many Prussian busbies were transformed in LH :
- for the need of studio photographers (less expensive to find a Prussian busby, buy a skull and crossed bones plate and fix it)
- for the need of theaters and costumehouses, in particular for the very popular theater piece " la dame aux camélias" featuring a Leib hussar character
- for the war-souvenir business, this picture with the American soldier carrying a LH (upgraded !) busby probably purchased the item from a reseller, he paid much more for a "LH" one than he would have paid for a Prussian,
- for post-war veteran associations and carnaval representations
- by collectors in the old times before the speculation took place on Imperial German headgear..... Missing a model but having a Prussian busby and an original (or old at least) plate ? no problem ! I pierce the leather and place my plate, that's just for my pleasure and my display !
Give a look at this picture, it's taken in the MRA museum in Brussels, this one has the proper bandeau, I don't say that this busby is unmessed with, you need to have it in hands to say it, .....when the bandeau is waved then the skull plate is too low and is not estetically placed on the busby, you see at once that it's a modification !
concerning period pictures, the only 100% reliable source is the pic taken in the field, otherwise there's always a doubt on the reality of the pic, I have a number of women photographied in Feldgrau uniform

.... at home ! just to joke, wearing their husband's or brother's uniform !
concerning your last question, it's difficult to sort old repros and originals, they were sometimes produced in the 20s or 30s by the same firm, with the same machines, I've seen a number of them and did not buy any, I will spend some money the day I'm quite sure it comes for instance from a damaged original busby or dug out ..... but other collectors could may be give some advice in that field

.... I think there was a post on this forum on this subject,
hope this helps
kind regards
Stephane