Is the LEGO 456-2 piece rare?

Yes, this piece is from the 1966 Supplemental theme and is a desirable vintage item for collectors.

What is the set number for this window piece?

The set number for this specific LEGO 1x2x2 Window is 456-2.

This piece was originally released in 1966.

Name: LEGO 1 x 2 x 2 Window, Red or White (456-2)
Brand: LEGO

Supplemental

Supplemental · 1966

Theme · SupplementalPieces · 15Set Number · 456-2Year · 1966

Used

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New / Sealed

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Is the LEGO 456-2 piece rare?: Yes, this piece is from the 1966 Supplemental theme and is a desirable vintage item for collectors.
What is the set number for this window piece?: The set number for this specific LEGO 1x2x2 Window is 456-2.
What year was this LEGO piece released?: This piece was originally released in 1966.