The NDC should come from the actual product used, either from the box or the label on the vial or syringe. If you have a Pharmacy, they should be able to provide that information. Otherwise, start with whomever in your office dispensed the medication.
J1050 is not in the ASP listing from CMS. According to Codify, J1050 has an Excluded status:
E = Excluded from Physician Fee Schedule by regulation. These codes are for items and/or services that CMS chose to exclude from the fee schedule payment by regulation. No RVUs are shown, and no payment may be made under the fee schedule for these codes. Payment for them, when covered, generally continues under reasonable charge procedures.
I found it on my MACs DME website as a supplier code eff 1/1/23. If that's relevant for you, see if you can find a similar site for your MAC's DME.