Alfke,
The more I look at the picture, the more I think I may be wrong in my initial assessment. The inner vertical walls on blue tops were white, the ones in the picture are brown. I am now leaning more towards the idea that those conversion kits were also used if someone needed to replace a brown top playfield, and that it what is pictured. The bigger overall comment is that it does have a replacement playfield, ramps and side strips, but doubtful it was originally a blue top. If you want to PM me your email, I'll send some pictures of what I am describing.
Tyler