I have 1 complete set that  does not have a key. Does work just fine. Removed only to upgrade to Badge access type lock.

Alarm Lock DL5200 Pushbutton Cylindrical Door Lock, Double Sided, 100 Users, Weatherproof, Straight Lever

Double-Sided: Access on both sides of the door

• Incorporates all of the important features of DL2700 (T2) into a double-sided lock

• Easy to add, delete, change users at the keypad (on primary side of door)

• Programming user codes on one side of the door works both sides, cutting your time & labor in half

• Ideal for community pool gates, courtyard gates, airport jetway doors, interrogation rooms, psych wards

• Comes with LED & audible entry indicators

• 100 user codes (3-6 digit codes)

• Battery operation: 5 AA’s; appx. 80,000 cycles; low battery alerts; lock may be hard-wired with 9VDC or 9VAC power supply for remote release / battery backup

• Visual and audible entry and egress indicators

• Weatherproof -31˚ to 151˚F (-35˚ to +66˚C) – water-sealed for exterior or interior use

• 5AA batteries operated, 80,000 cycles, typical

• Key override on primary door side (key cylinder on other side is to gain access to the battery compartment