To get a MD CLEO sign-off:

First - no appointment - you really have to be in Jessup on Thursday mornings in person.

1) Have your paperwork ready, but DONT SIGN the form 1's just yet. They have to witness it... more on that later. By paperwork ready, have your 2 form 1's, 2 blue ATF cards and your checkbook.
2) Once you make it to Jessup (the only place they can sign), go to the processing building (to the right of the "little brick building" with the wheelchair lift) and sign in. Sign up for three print cards (2X blue atf and 1X MSP orange).
3) They will take your ID and you will be called.
4) Get fingerprinted for your 2 blue ATF cards and for 1 "orange" MSP CJIS card. Ask them - the do keep the orange cards cards there.
5) It is 5 bucks per card - $15 typically for 3x. Bring CASH or CHECK - no plastic allowed.
6) Go out to your car and fill in the specifics of the "orange card" after your prints are on it - name, address, DL number, "I certify that I am not a felon", etc.
7) Go to the "little brick building in the center of the complex" and tell the woman you have C3 paperwork to drop off.
8) Sign both form 1's in front of them.
9) Stroke a check for $18 for exercising your second amendment rights.
10) Go home and WAIT.... at least 3 to 4 weeks will pass. Basically, the orange card goes to Pikesville and they make sure you are not Chester Molester. Once your orange card "background check" comes back clean, they will sign the forms and you will get them in your mailbox. Keep the orange card as a keepsake - the ATF doesn't need it after the CLEO signs it. If you decide to do more F4's or F1's, you still need to do this every time. I did find out they only need one per dealer, meaning if you have 2 items from a dealer you only need one orange card. Two seperate items from two seperate dealers requires two cards.... for what reason I don't even want to know.

One more tip - they only print on Thursday mornings 9-11ish. Get the old guy to do it! He is a reserve volunteer and he is the best (I think his name is Robert). I had a rookie do my prints once and he inked my fingers on each press. Pikesville rejected my prints as illegible and I had to do them again (free of course, by the older guy). If you think they are too dark, complain. If not, it will only add wait to getting your signed F4 or F1's back.

Quoted:
OP is from Delaware.  

The Federal laws are pretty clear.  However, I can’t find any definitive information on SBR’s in Delaware.  Delaware Law clearly states no Short Barreled Shotguns, but the law does not say anything about Rifles.

If you do need fingerprinting and/or background check done, the Delaware State Bureau of Identification would be the office to contact.  They do it at the State Police Barracks.
Link to website is HERE

Let us know what you find and how you make out.