The older WDI4500 scanner (by default) will change case of scanned alpha characters (letters) based on how a USB keyboard's caps lock state is set. For example, if the barcode data is ABcd1234, with caps lock off, the scanner sends ABcd1234. With caps lock on, the scanner sends abCD1234.
Can the newer WDI4600 scanner be programmed for this behavior? No. The WDI4600 uses a different scan engine from the WDI4500, and some features are different.
In the Product Reference Guide, printed Page 55 (PDF page 65) has the available case conversion barcodes. There is not a per-character "toggle case" mode. These settings are not affected by the caps lock state of a keyboard also connected to the PC. (Remember to scan "Enter/Exit Programming Mode" before and after any configuration barcodes.)
Disable (no case conversion) - default setting
Convert to upper case
Convert to lower case
The WDI4600's Product Reference Guide and Quick Start Guides can be downloaded here if necessary: