Replace special characters

I have a line ending with special character and 0
The special character is the field separator for this line
in VI mode the file will look like below, but while cat the special character wont display

i know the hexa code for the special character ^_ is \x1f and ascii code is
\0037,

000^_^_^_^_^_^_0.000000^_^_^_^_^_^_^_^_^_^_^_^_0^_0.000000^_^_^_^_0^_0^_^_^_0

I can filter these lines which is ending with ^_0 with the below command

grep `echo "\0037"`0$ filenam

Now my requirement is i want add one end delimiter to such lines.
simply i want replace the last ^_0with ^_0{}, where {} is the new sring i am going to add as an end delimeter

the whole file will look like this

30093354^_40^_1^_1^_615220181^_1324314123^_b0002
b00^_^_^_b0002
b0002/038513530400025^_2^_9^_3^_1324929600^_1^_1^_19.070000^_0.000000^_19.070000^_0.000000^_0.000000^_USD ^_1.000000^_USD ^_0^_1^_1^_1^_^_^_^_^_3^_^_2^_ ^_1324314123907^_^_^_^_0^_0.000000^_^_^_^_^_^_^_^_0^_0.000000^_^_^_^_0^_0^_^_^_0
68576101^_4^_1^_1^_628398181^_1323894124^_m1500
M15^_^_^_m1500
M1500/038513480015005^_2^_9^_3^_1324501200^_1^_1^_31.410000^_0.000000^_31.410000^_0.000000^_0.000000^_USD ^_1.000000^_USD ^_0^_0^_0^_0^_^_^_^_56^_3^_^_20^_ ^_1323894124565^_^_^_^_0^_0.000.000000^_^_^_^_^_^_^_^_^_^_^_^_0^_0.000000^_^_0^_0^_0^_0^_^_^_0

>

out put should be something like this

30093354^_40^_1^_1^_615220181^_1324314123^_b0002
b00^_^_^_b0002
b0002/038513530400025^_2^_9^_3^_1324929600^_1^_1^_19.070000^_0.000000^_19.070000^_0.000000^_0.000000^_USD ^_1.000000^_USD ^_0^_1^_1^_1^_^_^_^_^_3^_^_2^_ ^_1324314123907^_^_^_^_0^_0.000000^_^_^_^_^_^_^_^_0^_0.000000^_^_^_^_0^_0^_^_^_0{}
68576101^_4^_1^_1^_628398181^_1323894124^_m1500
M15^_^_^_m1500
M1500/038513480015005^_2^_9^_3^_1324501200^_1^_1^_31.410000^_0.000000^_31.410000^_0.000000^_0.000000^_USD ^_1.000000^_USD ^_0^_0^_0^_0^_^_^_^_56^_3^_^_20^_ ^_1323894124565^_^_^_^_0^_0.000.000000^_^_^_^_^_^_^_^_^_^_^_^_0^_0.000000^_^_0^_0^_0^_0^_^_^_0{}

>

---------- Post updated at 08:18 PM ---------- Previous update was at 08:21 AM ----------

I solved the issue, But for some reason i could'nt use the desired string '{}' but managed with '�'

perl -i -ne 's;(\x1F)0\n;\x1F0�\n;g;print;' file