"and has been provided an IRS Form 15400 stating the Maximum credit is $7,500. Is there a Federal"

Yes, you just pointed out this IRS form is for Federal.

You can look up the requirements and eligibility at:

https://www.irs.gov/credits-deductions/credits-for-new-clean-vehicles-purchased-in-2023-or-after

and:

https://fueleconomy.gov/feg/tax2023.shtml

But it seems you have the right form, already, as evidence your taxpayer has been reported:

https://www.tesla.com/support/ira-clean-vehicle-report/2023

MD has an excise tax credit:

https://mva.maryland.gov/Documents/VR-334.pdf

https://mde.maryland.gov/programs/air/mobilesources/pages/zev.aspx

• Federal Income Ta​x Credit up to $7,500 for the purchase of a qualifying Electric Vehicle or Plug-in Hybrid.
• Maryland Excise Tax Credit of ​$3,000 for qualifying zero-emission plug-in electric or fuel cell electric vehicles. ​​