diff --git a/cmd/orphan-finder/main.go b/cmd/orphan-finder/main.go
index 358dbdd50..875a36064 100644
--- a/cmd/orphan-finder/main.go
+++ b/cmd/orphan-finder/main.go
@@ -67,9 +67,7 @@ func checkDER(sai certificateStorage, der []byte) error {
 	if err == nil {
 		return errAlreadyExists
 	}
-	// TODO(#2600): Remove core.NotFoundError check once boulder/errors
-	// code is deployed
-	if _, ok := err.(core.NotFoundError); ok || berrors.Is(err, berrors.NotFound) {
+	if berrors.Is(err, berrors.NotFound) {
 		return nil
 	}
 	return fmt.Errorf("Existing certificate lookup failed: %s", err)
diff --git a/wfe/wfe.go b/wfe/wfe.go
index 355a76b04..1dd730bae 100644
--- a/wfe/wfe.go
+++ b/wfe/wfe.go
@@ -470,9 +470,7 @@ func (wfe *WebFrontEndImpl) verifyPOST(ctx context.Context, logEvent *requestEve
 	// Special case: If no registration was found, but regCheck is false, use an
 	// empty registration and the submitted key. The caller is expected to do some
 	// validation on the returned key.
-	// TODO(#2600): Remove core.NoSuchRegistrationError check once boulder/errors
-	// code is deployed
-	if _, ok := err.(core.NoSuchRegistrationError); (ok || berrors.Is(err, berrors.NotFound)) && !regCheck {
+	if berrors.Is(err, berrors.NotFound) && !regCheck {
 		// When looking up keys from the registrations DB, we can be confident they
 		// are "good". But when we are verifying against any submitted key, we want
 		// to check its quality before doing the verify.
@@ -486,9 +484,7 @@ func (wfe *WebFrontEndImpl) verifyPOST(ctx context.Context, logEvent *requestEve
 		// For all other errors, or if regCheck is true, return error immediately.
 		wfe.stats.Inc("Errors.UnableToGetRegistrationByKey", 1)
 		logEvent.AddError("unable to fetch registration by the given JWK: %s", err)
-		// TODO(#2600): Remove core.NoSuchRegistrationError check once boulder/errors
-		// code is deployed
-		if _, ok := err.(core.NoSuchRegistrationError); ok || berrors.Is(err, berrors.NotFound) {
+		if berrors.Is(err, berrors.NotFound) {
 			return nil, nil, reg, probs.Unauthorized(unknownKey)
 		}