Serial Number Specifics
Current production 90 series pistols built in Accokeek, MD, and Gallatin, TN facilities have serial numbers beginning with "BER". The older models started with "BER" and ended with a "Z" in 9mm, an "M" for .40 caliber.
90 series pistols produced by Beretta Italy can start with any single letter and end with any single letter. For example, an Italian M9A3 may be B12345Z.
There is no significance or difference in value if the serial number contains a letter character.
90 Series (US Made): BER
90 Series (Italian Made): Any alphabetical character
Wilson Combat 90 Series: WC
80 Series Cheetah: Any alphabetical character
Bobcat/Tomcat: DAA, or BES
U22 NEOS: T, P, or R
Px4 Storm: PX, PZ, PK, or PY
M9 Commercial: M9-
BU NANO: NU
A400: XA, SA, or WA
A400 Xcel Multitarget: ST
A300: RU, BU, or SU
A391: AA or AG
686 Silver Pigeon Line: Any alphabetical character
690 Series: SX, or any singular alphabetical character
Cx4 Storm: CX or CK
All Sako and Tikka rifles in modern production begin in one alphabetical character, older models were six digits.