If its something you really want - and you have the money ....I don't see tying it up on a backorder as a big deal ???
Most of my local dealers on custom orders...especially if they know you / will accept 50% down and balance on delivery - especially if its something they will have no trouble selling if the buyer flakes out on the deal. They have a business to run too - so I expect them to at least want enough down to pay for their order time, return, etc to mfg, if buyer flakes out.
Some of my local dealers, when they confirm the order will want 100% - especially if its under $1,500 - but I don't think that is unreasonable. It isn't the dealers fault - that things are backordered.
But if you don't want to tie up your money ...then see if the dealer has some on order - maybe they'll try and let you know when they come in ??
One of the guys on this forum ordered a custom 1911 from Wilson Combat recently ...about $ 3,800 as I recall...( I thought he was very smart to make the order - I like Wilson's guns a lot ) and I think they quoted him about a 9 month delivery time. But if he didn't get the order placed then ....today, that order time may be out to 18 months...its just the way things are right now. The mfg will do what they can ....but first to fully pay for the gun with their order...will get their guns first.
I've fully paid for guns I've custom ordered in the past ...for well over $2K ...and while delivery in the Old Days...was maybe 3 or 4 months..vs 9 - 18 months now...its still money spent - if I give it to them now or later it doesn't really matter - because I'll set the money aside. I'm only getting about 0.65% on $50,000 CD's right now anyway ....0.65% on $2K is only $13 so it isn't like I'm losing anything that valuable....( in my view ).