A fifth version exists that bears the model number 2194001-XX-XXX stamped into the bottom of the keyboard. In addition there is a specific model number (such as 2194001-00-002) on both a bar code sticker and a model number/serial number label that also includes a date such as "MAXI SWITCH MEXICO 01-21-95". This version has a PS/2-style plug and has five screws instead of the heat staked attachments.
