1991 Tahoe

I just bought a 91 Tahoe, and they sent me an unprogrammed remote, part number 15732803. Is this correct? I tried programming using these instructions, but to no avial- HELP, please!

[1] Start with the ignition switch in the OFF position

(Steps 2 thru 4 must be completed within 10 seconds or less)

[2] With all doors closed, hold down the power UNLOCK button
(Not Lock) on the driver side door panel.

[3] While holding down the UNLOCK button on driver side door panel
Turn the ignition switch to the ON position.
Turn the ignition switch to the OFF position.
Turn the ignition switch to the ON position.
Turn the ignition switch to the OFF position.

[4] Release the power Unlock button on the door panel. Your door lock receiver
will respond in the following manner in order to let you know the receiver is in
the programming mode:
Locking the doors
Unlocking the doors. (Click-Click)

[5] Hold down the Lock and Unlock buttons on the transmitter simultaneously
(up to 20 seconds) until the remote control door lock receiver responds in
the following manner:
Locking the doors.
Unlocking the doors. (Click-Click)

[6] Repeat step [5] for each additional transmitter. (up to 4 transmitters)

[7] Turn the ignition switch to the ON position in order to exit the transmitter programming mode