There were two different 600 MHz iMacs, one introduced in February 2001, the other in July.

The early 2001 600 MHz iMac retailed for US$1,499 and includes 128 MB of RAM (expandable to 1 GB), a 40 GB hard drive, and an 8x CD-RW drive. It uses Rage 128 Ultra graphics with 16 MB of dedicated video memory. It was available in graphite, Flower Power, and Blue Dalmatian, and it requires Mac OS 9.1 or later.

Details
•introduced 2001.02.22 at US$1,499; replaced by updated model on 2001.07.18
•requires Mac OS 9.1 through OS X 10.4.x
•CPU: 600 MHz PPC 750CXe (a.k.a. G3e)
•bus: 100 MHz
•performance:
◦Geekbench 2 (Tiger): 294
•RAM: 128 MB, expandable to 1,024 MB using two PC100 SDRAM (3.3 V, 64-bit, 168-pin, 100 MHz)
•VRAM: 16 MB SGRAM
•Video: supports resolutions of 640 x 480 at 117 Hz, 800 x 600 at 95 Hz, and 1024 x 768 at 75 Hz using ATI RAGE Ultra 128 chip set
•monitor: 15" (13.8" viewable) multiscan to 1024 x 768
•L2 cache: 256 KB on-chip cache running at full CPU speed
•hard drive: 40 GB Ultra ATA drive. Maximum IDE drive size is 128 GB without third-party support. See How big a hard drive can I put in my iMac, eMac, or Power Mac? for your options.
•CD-RW: 8x/4x/24x maximum throughput
•USB: 2 separate USB 1.1 ports and controllers
•FireWire: 2 FW400 ports
•modem: built in v.90 56k modem
•ethernet: 10/100Base-T
•WiFi: requires AirPort Card Adapter, 802.11b AirPort Card
•Microphone: internal
•power: 150W
•PRAM battery: 3.6V half-AA
•height: 15.0 in/38.1 cm
•width: 15.0 in/38.1 cm
•depth: 17.1 in/43.5 cm
•weight: 34.7 lb/15.8 kg
•part numbers: M7680 (graphite), M7675 (blue Dalmatian), M7679 (flower power)
•family numbers: M5521

OIur unit iis the earlier Blue Dalmatian edition M5521. Although it is a M7675 only the family name of M5521 is shown
The serial number is UM1060U8KJR

With thanks to http://lowendmac.com/imacs/600-mhz-imac-g3-early-2001.html for the specification

Manufacturer: Apple
Date: 22nd February 2001

This exhibit has a reference ID of CH5233. Please quote this reference ID in any communication with the Centre for Computing History.