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