Bandai's MachineRobo line has had several different changes in regards to their packaging over the years. The original Popy releases had a very classic look which was changed once they were absorbed into parent company Bandai. The G.K. sticker on all the boxes represents the logo of the Popy Ginza Planning Department. (It's possible that the G.K. stands for Ginza Kaisha.) This division was founded in 1981, and in 1985 they officially changed their name to PLEX.

Below is a guide to the 600 series MachineRobo Japanese packaging

First Version - 1982

These Popy branded boxes were the first editions released. Starting in 1982, the first 7 releases in the line had this packaging. The silver box with red band was short lived, being replaced in 1983 when Bandai absorbed Popy.

Carded First Version - 1982-1983

The first 7 MachineRobo toys were also released on blister card and are quite rare. Note both the Bandai and Popy logos on the packaging. The back of the blister cards are blank.

Second Version - 1982-1983

Popy's transitional packaging featured a horizontal color stripe across the front with bold numbering. Toys were featured in robot mode on one side and vehicle mode on the other. Depending on the stage of release, some of these packages have both Bandai and Popy logos on them. Earlier releases just have the Popy logo.

Third Version 1983-1984

Now transitioned over to Bandai but still retaining Popy branding, this packaging featured a double horizontal color stripe across the front with bold numbering. Toys were featured in robot mode on one side and vehicle mode on the other. Depending on the stage of release, some of these packages have both Bandai and Popy logos on them. Earlier releases just have the Popy logo.

Fourth Version 1983-1984

This year was the first to do away with Popy branding and now was a fully Bandai release. During this year many Bandai releases, not limited to MachineRobo, included this rainbow band across the packaging. Toys were featured in robot mode on one side and vehicle mode on the other.

 

Fifth Version - 1986

When Bandai launched the Battle Hackers sub-line in 1986, they re-released older MachineRobo toys under a new numbering system. Toys were featured in robot mode on one side and vehicle mode on the other.