Before upgrading the RAM in my Macbook, I had to find out which revision it was. Reboot wasn't an option since I did not want to lose my 39 days of uptime, so I had to find a linux-based solution - dmidecode:
$ sudo dmidecode --type 1
# dmidecode 2.9
SMBIOS 2.4 present.
Handle 0x0001, DMI type 1, 27 bytes
System Information
Manufacturer: Apple Inc.
Product Name: MacBook2,1
Version: 1.0
Serial Number: N0N3EDTOFE3D
UUID: S0M3TH1N5-57RAN53-15-H3RE-70-C
Wake-up Type: Power Switch
SKU Number: System SKUNumber
Family: MacBook