If you use out-of-bailiwick nameservers (like in your test case) and you do not use DNSSEC (you did not say) then you are right, the 3
NS records will be the only things inserted in the parent zone related to your domain.
1) Out-of-bailiwick nameservers
As long as you use nameservers that are not "in" your own zone, you are using out-of-bailiwick nameservers and hence the registry does not need to publish glue records.
On the contrary, if you decided to use
ns1.example.com as nameserver for
example.com, then, to resolve the chicken-and-egg problem you just created, the registry will also need to publish a glue record for
ns1.example.com which just means basically one or multiple
AAAA records for this nameserver. This will of course need to be done through the registrar.
And you will need later to make sure that this gets updated each time the IP addresses of this server change, otherwise major problems will occur.
If you decide to activate DNSSEC on your domain, then the parent zone needs to publish one or more DS records for your zone. This is again done through the registrar but it also depend on what the registry wants to receive (basically either a DS or a DNSKEY, in the latter case it means the registry generates the DS by itself from the DNSKEY), and which algorithms they allow (which change your list of options for your DS/DNSKEY records).
The registry will also publish RRSIG records on your DS record(s), to enable the whole chain of trust that validating resolvers will be able to check at each DNS exchange.
The NS records themselves are not covered by RRSIG records, irrespective to the fact that they are in the AUTHORITY section (but they are signed inside the child zone of course). And glue records, that is
AAAA records corresponding to targets of the
NS records are in the
ADDITIONAL section, and so without associated
RRSIG records also.