What I would like to do is just the 737NG check and get currency that way afterall it is the same type
You cant, you need to do a conversion course from CL to NG.A sim check is not enough to be NG qualified.
Some chinese airlines did offer jobs to classic pilots,offering a conversion course, but not anymore as far as i m aware.
Airlines in china need currency up to 18 months,i think they wont stretch it any longer.