I would agree with both, but as @mouviciel noted the order of the words would be different.
In fact I would go for :

La gamme 700/7000 d’IBM

In this context, a gamme is a range of products while a série is a sequence of products.

They might be interchangeable like in your example but beware that it is not always the case.

A gamme often encompass the whole range of the products a manufacturer is building while a serie is a subset of it.

For example, the gamme of cars sold by BMW is a suite of séries: Série 1, Série 2, Série 3 and so on.

There are also some idioms like:

• Fin de série: The last models of a kind being produced.

• Série limitée: A short number of models produced with specific features (either optional ones included for the same price, or unique features or quality). Compare to Gamme limitée that means a narrow range of products.

There is also de série that means either being included in the standard model (opposed to en option), or being available as a standard model (opposed to prototype or sur mesure).