Actually, the first year (1958) Bearcats were all 3 digits,, (1-999). Then they went to the Alphabet Series, (1958-1960.) Also in 1960 they started with 1000, 1001, skipped some, & went from 2000 to 5599. In 1961,, it was 5600 to 17467.
RENE price guide;
1-999 serials; $895
Alphabet Cats; $555
Small serial numbers; $480
So a 4 digit,,, with small numbers in excellent condition about $480.